I created a Harry Potter world, not sure how to go about playing Hogwarts.

I'd make it a community lot. Probably a school of some kind. Do you have Lunar Lakes? I have used those tiny little futuristic community buildings before and built the building I wanted around it. Did a very modernistic police station and city hall once and put the tiny community bldgs. in a basement under it. They seemed to function okay. (I wasn't sure how else to do it).