diff --git a/CHANGELOG.md b/CHANGELOG.md
index bfa7d2d..e5be3cd 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,3 +1,7 @@
+### HEAD
+* Return instead of echo class names in `roots_main_class` and `roots_sidebar_class`
+* Move nav customizations into `lib/nav.php`
+
 ### 6.1.0: October 2nd, 2012
 * Change roots_sidebar into a more explicit configuration array
 * Re-organize configuration/setup files
diff --git a/README.md b/README.md
index c3f7fac..d4bdaf4 100644
--- a/README.md
+++ b/README.md
@@ -9,7 +9,9 @@ Roots is a starting WordPress theme made for developers that’s based on [HTML5
 
 ## Configuration
 
-Edit `lib/config.php` to enable support for major functionality and to define constants that are used throughout the theme.
+Edit `lib/config.php` to enable or disable support for various theme functions and to define constants that are used throughout the theme.
+
+Edit `lib/init.php` to setup custom navigation menus and post thumbnail sizes.
 
 ## Documentation
 
@@ -37,12 +39,12 @@ Everyone is welcome to help [contribute](/retlehs/roots/blob/master/CONTRIBUTING
 * Writing or editing [docs](/retlehs/roots/blob/master/doc/TOC.md)
 * Writing or refactoring code
 * Fixing [issues](https://github.com/retlehs/roots/issues)
-* Replying to questions on the [mailing list](http://groups.google.com/group/roots-theme)
+* Replying to questions on the [Google Group](http://groups.google.com/group/roots-theme)
 
 ## Project information
 
 * Source: [https://github.com/retlehs/roots](https://github.com/retlehs/roots)
 * Web: [http://www.rootstheme.com/](http://www.rootstheme.com/)
-* Mailing list: [http://groups.google.com/group/roots-theme](http://groups.google.com/group/roots-theme)
-* Twitter: [@retlehs](https://twitter.com/#!/retlehs)
+* Google Group: [http://groups.google.com/group/roots-theme](http://groups.google.com/group/roots-theme)
+* Twitter Updates: [@retlehs](https://twitter.com/#!/retlehs)
 * Contributors: [https://github.com/retlehs/roots/contributors](https://github.com/retlehs/roots/contributors)
\ No newline at end of file
diff --git a/base.php b/base.php
index 02e31ed..9133ed7 100644
--- a/base.php
+++ b/base.php
@@ -14,11 +14,11 @@
 
   <div id="wrap" class="container" role="document">
     <div id="content" class="row">
-      <div id="main" class="<?php roots_main_class(); ?>" role="main">
+      <div id="main" class="<?php echo roots_main_class(); ?>" role="main">
         <?php include roots_template_path(); ?>
       </div>
       <?php if (roots_display_sidebar()) : ?>
-      <aside id="sidebar" class="<?php roots_sidebar_class(); ?>" role="complementary">
+      <aside id="sidebar" class="<?php echo roots_sidebar_class(); ?>" role="complementary">
         <?php get_template_part('templates/sidebar'); ?>
       </aside>
       <?php endif; ?>
diff --git a/doc/lib.md b/doc/lib.md
index fa89bbf..833ff69 100644
--- a/doc/lib.md
+++ b/doc/lib.md
@@ -28,12 +28,7 @@ If you don't want to use one of the features, either comment out the line or rem
 
 #### Define which pages shouldn't have the sidebar
 
-`roots_sidebar()` is used to define which pages shouldn't get the sidebar. By default, the 404 and `page-custom.php` template are full width. If you would like to remove the sidebar from additional pages, add in a proper conditional to the first `if` statement.
-
-If you had a page named Contact, you would update the statement to look like:
-
-    if (is_404() || is_page_template('page-custom.php') || is_page('contact')) {
-
+`roots_display_sidebar()` is used to define which pages shouldn't get the sidebar. By default, the 404, front `front-page.php` and `page-custom.php` templates are full width. If you would like to remove the sidebar from additional pages, add in the appropriate conditional or page template name.
 
 ### h5bp-htaccess
 
@@ -59,6 +54,10 @@ This file runs the initial theme setup and defines helper constants for later us
 
 This file is a placeholder for you to put in custom metaboxes. We recommend the use of [Custom Metaboxes and Fields for WordPress](https://github.com/jaredatch/Custom-Metaboxes-and-Fields-for-WordPress).
 
+### nav.php
+
+This file contains all the custom nav modifications (for Bootstrap) and clean up.
+
 ### post-types.php
 
 This file is a placeholder for you to put in [custom post types](http://codex.wordpress.org/Function_Reference/register_post_type) and [taxonomies](http://codex.wordpress.org/Function_Reference/register_taxonomy).
diff --git a/functions.php b/functions.php
index c2a1d0e..08c0bbf 100644
--- a/functions.php
+++ b/functions.php
@@ -11,6 +11,7 @@ require_once locate_template('/lib/sidebar.php');         // Sidebar class
 require_once locate_template('/lib/config.php');          // Configuration
 require_once locate_template('/lib/activation.php');      // Theme activation
 require_once locate_template('/lib/cleanup.php');         // Cleanup
+require_once locate_template('/lib/nav.php');             // Custom nav modifications
 require_once locate_template('/lib/htaccess.php');        // Rewrites for assets, H5BP .htaccess
 require_once locate_template('/lib/widgets.php');         // Sidebars and widgets
 require_once locate_template('/lib/scripts.php');         // Scripts and stylesheets
diff --git a/lib/cleanup.php b/lib/cleanup.php
index e4d25f9..ac5666c 100644
--- a/lib/cleanup.php
+++ b/lib/cleanup.php
@@ -160,7 +160,7 @@ function roots_fix_duplicate_subfolder_urls($input) {
   $output = roots_root_relative_url($input);
   preg_match_all('!([^/]+)/([^/]+)!', $output, $matches);
 
-  if (isset($matches[1]) && isset($matches[2])) {
+  if (isset($matches[1][0]) && isset($matches[2][0])) {
     if ($matches[1][0] === $matches[2][0]) {
       $output = substr($output, strlen($matches[1][0]) + 1);
     }
@@ -407,107 +407,6 @@ function roots_excerpt_more($more) {
 add_filter('excerpt_length', 'roots_excerpt_length');
 add_filter('excerpt_more', 'roots_excerpt_more');
 
-/**
- * Cleaner walker for wp_nav_menu()
- *
- * Walker_Nav_Menu (WordPress default) example output:
- *   <li id="menu-item-8" class="menu-item menu-item-type-post_type menu-item-object-page menu-item-8"><a href="/">Home</a></li>
- *   <li id="menu-item-9" class="menu-item menu-item-type-post_type menu-item-object-page menu-item-9"><a href="/sample-page/">Sample Page</a></l
- *
- * Roots_Nav_Walker example output:
- *   <li class="menu-home"><a href="/">Home</a></li>
- *   <li class="menu-sample-page"><a href="/sample-page/">Sample Page</a></li>
- */
-class Roots_Nav_Walker extends Walker_Nav_Menu {
-  function check_current($classes) {
-    return preg_match('/(current[-_])|active|dropdown/', $classes);
-  }
-
-  function start_lvl(&$output, $depth = 0, $args = array()) {
-    $output .= "\n<ul class=\"dropdown-menu\">\n";
-  }
-
-  function start_el(&$output, $item, $depth = 0, $args = array(), $id = 0) {
-    $item_html = '';
-    parent::start_el($item_html, $item, $depth, $args);
-
-    if ($item->is_dropdown && ($depth === 0)) {
-      $item_html = str_replace('<a', '<a class="dropdown-toggle" data-toggle="dropdown" data-target="#"', $item_html);
-      $item_html = str_replace('</a>', ' <b class="caret"></b></a>', $item_html);
-    }
-    elseif (in_array('divider-vertical', $item->classes)) {
-      $item_html = '<li class="divider-vertical">';
-    }  
-    elseif (in_array('divider', $item->classes)) {
-      $item_html = '<li class="divider">';
-    }
-    elseif (in_array('nav-header', $item->classes)) {
-      $item_html = '<li class="nav-header">' . $item->title;
-    }
-
-    $output .= $item_html;
-  }
-
-  function display_element($element, &$children_elements, $max_depth, $depth = 0, $args, &$output) {
-    $element->is_dropdown = !empty($children_elements[$element->ID]);
-
-    if ($element->is_dropdown) {
-      if ($depth === 0) {
-        $element->classes[] = 'dropdown';
-      } elseif ($depth === 1) {
-        $element->classes[] = 'dropdown-submenu';
-      }
-    }
-
-    parent::display_element($element, $children_elements, $max_depth, $depth, $args, $output);
-  }
-}
-
-/**
- * Remove the id="" on nav menu items
- * Return 'menu-slug' for nav menu classes
- */
-function roots_nav_menu_css_class($classes, $item) {
-  $slug = sanitize_title($item->title);
-  $classes = preg_replace('/(current(-menu-|[-_]page[-_])(item|parent|ancestor))/', 'active', $classes);
-  $classes = preg_replace('/((menu|page)[-_\w+]+)+/', '', $classes);
-
-  $classes[] = 'menu-' . $slug;
-
-  $classes = array_unique($classes);
-
-  return array_filter($classes, 'is_element_empty');
-}
-
-add_filter('nav_menu_css_class', 'roots_nav_menu_css_class', 10, 2);
-add_filter('nav_menu_item_id', '__return_null');
-
-/**
- * Clean up wp_nav_menu_args
- *
- * Remove the container
- * Use Roots_Nav_Walker() by default
- */
-function roots_nav_menu_args($args = '') {
-  $roots_nav_menu_args['container'] = false;
-
-  if (!$args['items_wrap']) {
-    $roots_nav_menu_args['items_wrap'] = '<ul class="%2$s">%3$s</ul>';
-  }
-
-  if (current_theme_supports('bootstrap-top-navbar')) {
-    $roots_nav_menu_args['depth'] = 3;
-  }
-
-  if (!$args['walker']) {
-    $roots_nav_menu_args['walker'] = new Roots_Nav_Walker();
-  }
-
-  return array_merge($args, $roots_nav_menu_args);
-}
-
-add_filter('wp_nav_menu_args', 'roots_nav_menu_args');
-
 /**
  * Remove unnecessary self-closing tags
  */
diff --git a/lib/config.php b/lib/config.php
index 8e8640d..6b9ec43 100644
--- a/lib/config.php
+++ b/lib/config.php
@@ -20,6 +20,12 @@ function roots_display_sidebar() {
     /**
      * Conditional tag checks (http://codex.wordpress.org/Conditional_Tags)
      * Any of these conditional tags that return true won't show the sidebar
+     *
+     * To use a function that accepts arguments, use the following format:
+     *
+     * array('function_name', array('arg1', 'arg2'))
+     *
+     * The second element must be an array even if there's only 1 argument.
      */
     array(
       'is_404',
@@ -40,15 +46,17 @@ function roots_display_sidebar() {
 // #main CSS classes
 function roots_main_class() {
   if (roots_display_sidebar()) {
-    echo 'span8';
+    $class = 'span8';
   } else {
-    echo 'span12';
+    $class = 'span12';
   }
+
+  return $class;
 }
 
 // #sidebar CSS classes
 function roots_sidebar_class() {
-  echo 'span4';
+  return 'span4';
 }
 
 // Configuration values
diff --git a/lib/nav.php b/lib/nav.php
new file mode 100644
index 0000000..195a04d
--- /dev/null
+++ b/lib/nav.php
@@ -0,0 +1,101 @@
+<?php
+
+/**
+ * Cleaner walker for wp_nav_menu()
+ *
+ * Walker_Nav_Menu (WordPress default) example output:
+ *   <li id="menu-item-8" class="menu-item menu-item-type-post_type menu-item-object-page menu-item-8"><a href="/">Home</a></li>
+ *   <li id="menu-item-9" class="menu-item menu-item-type-post_type menu-item-object-page menu-item-9"><a href="/sample-page/">Sample Page</a></l
+ *
+ * Roots_Nav_Walker example output:
+ *   <li class="menu-home"><a href="/">Home</a></li>
+ *   <li class="menu-sample-page"><a href="/sample-page/">Sample Page</a></li>
+ */
+class Roots_Nav_Walker extends Walker_Nav_Menu {
+  function check_current($classes) {
+    return preg_match('/(current[-_])|active|dropdown/', $classes);
+  }
+
+  function start_lvl(&$output, $depth = 0, $args = array()) {
+    $output .= "\n<ul class=\"dropdown-menu\">\n";
+  }
+
+  function start_el(&$output, $item, $depth = 0, $args = array(), $id = 0) {
+    $item_html = '';
+    parent::start_el($item_html, $item, $depth, $args);
+
+    if ($item->is_dropdown && ($depth === 0)) {
+      $item_html = str_replace('<a', '<a class="dropdown-toggle" data-toggle="dropdown" data-target="#"', $item_html);
+      $item_html = str_replace('</a>', ' <b class="caret"></b></a>', $item_html);
+    }
+    elseif (stristr($item_html, 'li class="divider')) {
+      $item_html = preg_replace('/<a[^>]*>.*?<\/a>/iU', '', $item_html);    
+    }
+    elseif (stristr($item_html, 'li class="nav-header')) {
+      $item_html = preg_replace('/<a[^>]*>(.*)<\/a>/iU', '$1', $item_html);
+    }   
+
+    $output .= $item_html;
+  }
+
+  function display_element($element, &$children_elements, $max_depth, $depth = 0, $args, &$output) {
+    $element->is_dropdown = !empty($children_elements[$element->ID]);
+
+    if ($element->is_dropdown) {
+      if ($depth === 0) {
+        $element->classes[] = 'dropdown';
+      } elseif ($depth === 1) {
+        $element->classes[] = 'dropdown-submenu';
+      }
+    }
+
+    parent::display_element($element, $children_elements, $max_depth, $depth, $args, $output);
+  }
+}
+
+/**
+ * Remove the id="" on nav menu items
+ * Return 'menu-slug' for nav menu classes
+ */
+function roots_nav_menu_css_class($classes, $item) {
+  $slug = sanitize_title($item->title);
+  $classes = preg_replace('/(current(-menu-|[-_]page[-_])(item|parent|ancestor))/', 'active', $classes);
+  $classes = preg_replace('/((menu|page)[-_\w+]+)+/', '', $classes);
+
+  $classes[] = 'menu-' . $slug;
+
+  $classes = array_unique($classes);
+
+  return array_filter($classes, 'is_element_empty');
+}
+
+add_filter('nav_menu_css_class', 'roots_nav_menu_css_class', 10, 2);
+add_filter('nav_menu_item_id', '__return_null');
+
+/**
+ * Clean up wp_nav_menu_args
+ *
+ * Remove the container
+ * Use Roots_Nav_Walker() by default
+ */
+function roots_nav_menu_args($args = '') {
+  $roots_nav_menu_args['container'] = false;
+
+  if (!$args['items_wrap']) {
+    $roots_nav_menu_args['items_wrap'] = '<ul class="%2$s">%3$s</ul>';
+  }
+
+  if (current_theme_supports('bootstrap-top-navbar')) {
+    $roots_nav_menu_args['depth'] = 3;
+  }
+
+  if (!$args['walker']) {
+    $roots_nav_menu_args['walker'] = new Roots_Nav_Walker();
+  }
+
+  return array_merge($args, $roots_nav_menu_args);
+}
+
+add_filter('wp_nav_menu_args', 'roots_nav_menu_args');
+
+
diff --git a/lib/sidebar.php b/lib/sidebar.php
index 26c4e00..3d783ee 100644
--- a/lib/sidebar.php
+++ b/lib/sidebar.php
@@ -29,7 +29,11 @@ class Roots_Sidebar {
   }
 
   private function check_conditional_tag($conditional_tag) {
-    return $conditional_tag();
+    if (is_array($conditional_tag)) {
+      return call_user_func_array($conditional_tag[0], $conditional_tag[1]);
+    } else {
+      return $conditional_tag();
+    }
   }
 
   private function check_page_template($page_template) {