How to disable admin area of WP, but allow CPT creation?

Hi there. I would like that when user join my website, he can't see site dashboard or any backend. User should only be able to comment. And when I make custom post type that will be similar to posts, he would be able to access custom back for this posts. Is there a plugin I could use to create this? Something like this plugin http://wordpress.org/extend/plugins/custom-post-type-creator/? And than I can just disable admin bar? Is this the way to go?
Thanks & Cheers.