Sure! I'm thinking three levels.

Hangar level, (the top), which is devoted entirely to the hangar/entrance bits, and has a big elevator to the second level, and stairs. obviously.
Personnel level, which is the actual 'basey' part, with the barracks, armory, control room, briefing room (connected to the hallway that leads to the stairs, that go up to the hangar, if that makes sense).
And the Maintenance level, which has all of the base's storages and has the primary generator room and all, also much more heavily armored back-up command facilities in case of attack.