I would say take alook at some of the colleges in your area and look at what kits have elements you can use from them. For example the main campus of the University of Pittsburgh is a tall skycraper nicknamed the "Cathedral of Learning" in the heart of Pittsburgh. Surrounding it are the sports arenas for the various teams it has and bookstores. The community college I went to was built in a slightly modified Westinghouse plant. It was retrofitted with wheel chair ramps, annexes for a bookstore along with a baseball field, and a small shelter with a clocktower. The inside of the plant had been divided into classrooms and a gymnasium. Over time more buildings were added to the campus.
What would help tie all of these kits together most is the buildings can have a school logo or flag somewhere on them.