load custom CSS/JS for each CKEditor instance on page I would like to find out  the best way to load custom CSS/JS for each textarea with CKEditor. For me, each Content Type has different CSS/JS and I would like to load them with the CKEditor on that particular page.

How do I hook into the CKEditor module to do just that? 

P.S CKEditor is an independent module and not part of WYSIWYG Drupal Setup.
use hook_page_build to add or remove css or js files to the page based on the url. See the examples module for developers on how to add/remove js or css and to examples of render arrays.

your question is not so much about the CKeditor module or WYSIWYG module -- just how to customize css and js on specific criteria such as the page url.