I play with aging on only for the active family for all but one household. That way the townies can age with my Sims. As long as your students are in off campus housing this still works. My sim weeks start at 6am Saturday morning so I'm not messing with anyone's work schedule with the added benefit my students have all weekend to knock out any presentations and term papers as well as get their first homework assignments done.
As there are several lots in Britechester you can pretty much make your own dorms. The graduation ceremony isn't that big a deal (rabbit hole) so I'm fine missing it. I haven't played any Sims in an actual dorm but from what I've read it sounds more annoying than anything else.
After final grades come out on Friday evening just cancel the window to re-enroll for the next term and your students get a casual Friday night to go out and celebrate end of term before you rotate back to your families.
