[ElfMage]

Some pointers:
- current forum: $forumid, $foruminfo
- current user: $vbulletin->userinfo, (or $bbuserinfo if called from a template)
- current user permissions: $permissions
- current user name: $vbulletin->userinfo['username']
- parent forum ids: $foruminfo['parentlist']
- child forum ids: $foruminfo['childlist']

I am sure there is a tutorial somewhere explaining the basics.

I would suggest you find a mod that does something similar or at least in the area of what you intend to do, and study how they do it...