Living on campus has the advantage of close proximity to campus but is often more expensive and like dorm-life.
Some graduate students do like it and swear by it.
Thus, it is something to check. Living off-campus in an apartment seems to be the better choice for graduate students in the Physics Department especially those with families. There are many different apartment complexes in and around Norman, OK that offer great places to live. Below is a Norman Apartment Listing where you can find out a little about the many apartment complexes. Also, don't rent a place over the phone without looking at the place first.