I assume that your custom post type windows would map onto /windows/ etc?
You can customise the template for individual custom post types via single-posttype.php in your theme, e.g. single-windows.php single-doors.php and single-garages.php Wordpress will automatically pick these up
You could also use custom page templates, e.g. page-windows.php or custom templates with the right template names.
If the pages are intended to list the post types, then you could try creating post archive templates, e.g.: http://mark.mcwilliams.me/2010/10/wordpress-3-1-introduces-custom-post-type-archives/
Or, you could create a taxonomy for each of said names, and use taxonomy-windows.php
Using all fo the above, one could share the code using something along the lines of:
// example code, may need minor modifications
Allowing you to share the code for all the pages in one file, and giving you child theme support, and the ability to override via files such as special-windows.php
OR, if none of the above suit you, there is a final solution:
This will let you put a page with whatever you want, wherever you want, without needing any posts or pages of any kind, in a theme independent way.