Headway is a Wordpress plugin that lets you Drag & Drop yourself to a custom theme. At first, it isn't obvious how to setup a custom 404 page, but if you're an experienced Headway user, just set your layout's content block to a custom query. And as with all posts on PHP, this post exists to help the other poor souls that have to exist in PHP world, not to endorse the continued existence of PHP or Wordpress.
This site uses the Bootstrap Molokai theme, which I based off of the Molokai Vim color scheme. Converting a Vim color scheme to a Bootstrap theme is fairly easy but somewhat time-consuming. This post documents the process used for creating the Bootstrap Molokai theme.