Wordpress - Use WordPress page instead of post type archive
This one's actually pretty easy. When you declare your post type using register_post_type, you need to add a new argument for 'has_archive'.
So you'll add in something to the effect of:
'has_archive' => 'about-cool-post-types'
Then, go to your Settings > Permalinks to flush them and it should work. I tested it locally, and this seems to be the way to automatically generate your archive page at a different URL. Then, you should be able to create a page at the CPT's slug.
There's also a simple, 1-file plugin for this now, by the HumanMade folk;
https://github.com/humanmade/page-for-post-type
(Meta: I know answers with links aren't generally great, but I don't just want to copy and paste the source-code for that thing into an answer. What's the best strategy for this type of thing?)