The ARB does not control quota allocation. That's the job of the Quota Review Board (QRB). The ARB will make sure that a proposal for a quota reimbursement is in place when a room is linked to a public area.
If you want to link a private room to an area zoned for housing in the main area, the ARB is only interested in how you've described and messaged your exit from that zone into your private area.
The ARB wants to see lots of interesting public building. It is not our goal to simply be bureaucratic and vote "yay" or "nay" on rooms. We want to help players make their rooms linkable. We'll work with players to get their rooms to that stage if they're almost qualifying when a link is requested. We'll also answer questions and discuss ideas with players who are just contemplating a public building.
2) Your room must be public to be linked to a public area. This means that it must be unlocked and must be a room that any MOOer can use. It must be a room of some kind of public nature. It is *highly* unlikely that a bedroom will qualify under the public test -- even though it's unlocked. That kind of private building can be linked to hubs zoned for housing, can exist entirely in limbo, or could be linked to other players' private areas. However, this doesn't mean that your room will be disqualified from being a public room just because you've @sethome there. Where you choose to @sethome has no relevance to the test of a room's public nature.
3) Your room must be themely.
If you wish to link to the City area, your room should be something that would exist in a real life large city with high rises, gridlocked traffic, and all the rest. The City has a couple of interesting twists you might consider: a New Orleans area with the flavor of the French Quarter, and a Time Travel Museum for historical reproductions and futuristic fantasies.
If you wish to link to the Town area, your room should be something that would exist in a real life small town, or its surrounding farmland countryside.
If you wish to link to the Nature area, your room should be something that exists outdoors... trees, mountains, waterfalls, meadows, campgrounds and all the rest. No modern "buildings" will be linked to the Nature area. There are a couple of interesting twists here as well: an Elven community in the trees, and another community in the caves under the mountains.
If you're working on a really super public room and you can't figure out if it fits in any theme, have a chat with an ARB member. They'll try to help you with suggestions for where it could fit. It may only need a really creative exit message explaining the transition from an area to your room. If your room breaks completely new ground, passes the other tests for linkage, and simply can't fit into the structure that exists, the ARB can create a new attach point for a theme that would work.
4) Don't violate 'help manners' or 'help ethics'. Don't create rooms that will offend people. Don't put words into your visitors' mouths when they use your room. Don't tell them what they are thinking -- let the description itself do that work.
5) Be original and interesting. Once an area has a diner, it will be harder to get another diner linked there. That doesn't mean it can't be done, but the new building does have to distinguish itself in a meaningful way from the existing building. Interactivity in the room definitely adds interest. Creatively programmed verbs or creative message setting on the child of a generic will make the room score higher on this test. If you do have good ideas for a diner that would improve an existing diner, you might consider talking to the owner of the existing diner about incorporating your ideas.