One word: random.
Really. You're randomly selected for a freshman dorm, then at the end of your freshman year, you can choose "block mates", and the university will ensure that you and your block mates are put into the same house. But then your group is put into a lottery for housing. Therefore, there really can't be any cultural differences besides the amenities of the dorms and what develops from the people in your house, and I doubt that they would have different prices considering that it's a random deal in the first place.
In regard to changing the room, I think they even regulate what kinds of sticky stuff you can use on your walls, so I doubt painting is in the picture (no pun intended).