+1 on the FAK. That and something to block the door (like the teacher's desk if tipped and some wedges) is where I would start. Individual class rooms are hard to do.

Making sure the dining hall has the ability to handle the students + faculty + staff + 50% (parents heading there) for three meals with water would be my next stop. That and a genny with an autostart that is run off your heating oil/gas supply.