Dave's request to block off two full days to work on his project is probably legitimate, though you may want to get a bit more information about precisely what it is he's doing. Unless there's some overwhelming reason why he needs to be available for other things, he should probably be left alone to do his work.

Rhonda's desire to move her desk is the kind of request that managers tend to abhor, for several reasons. For one thing, they're a pain in the neck; managers generally feel that they have enough on their plate and don't want to have to deal with things that may seem personal and trivial. They often feel that people should just take what they're given. For another, such requests can open the door to a lot of similar requests from other employees. Managers often brush them off out of hand.

But this can be a mistake. Rhonda's request sounds like the classic plea of an introvert not to be treated like an extravert. Introverts really do have trouble working...