I am creating a multi-user WordPress and K2 based website that will consist of 4 distinct sections (categories?).  Each section will have its own look and feel but may have pages and posts (and other resources) that are shared between them (cross-categorized).  The website administrator must be able to assign users to a specific section (or better, assign a section by access level to specific users/groups of users). 

So User A1 has administrative access to Category A (or section A) while User A2 only has access to edit/publish pages and to uploading images (no access to posts).  User B1 has administrative access to Category B while User B2 limited access and so on.  I was hoping to use the following WordPress plugins to accomplish that task:

1. Page Category Plus which allows one to assign categories to pages (not a native WordPress function). This gives WP a truer CMS functionality.
2. Role Manager which allows one to manage WP Roles (and define new ones) and assign/withdraw specific capabilities to those roles.  It also allows one to manage individual WP User Profiles enabling the administrator to assign/withdraw specific capabilities over and above what the user's assigned Role allows.
3. Role Scoper which allows one to assign reading, editing or administration roles to users or groups on a page-specific, category-specific or content-specific basis.
4. Register Plus which allows the administrator to control private membership.

I am struggling with wrapping my mind around how these plugins interelate with each other and WP.  (Wouldn't it be nice if WP had all these capabilities built in to the core? ) 

I have read the Role Scoper usage guide and it sounds like the very thing I need but I am floundering as to how to set it up. If anyone has advice for me I welcome it!

Here is my test site: dev1.nbseminary.com