I'm trying to customize the admin interface so when i create a user, they only have access to see the upload screen, the gallery, and any videos they have access to. Any ideas on how to do that? The gallery would be their own gallery that they can edit and what not from the admin, not the gallery that is shown on the home page.

Assign only the rights the user needs then he will only see what he is allowed to. You can assign for example one (or more) toplevel album to a user and he can only editi this one. See the user guide about the user right management