when it comes to the bases, you'd propably be best off detatching stuff per smoothinggroup and element. you'll end up with alot of objects, but you'll end up with it running more efficient, since i'm guessing that's where most picke-ups and such would be (all of which have dynamic lights) cutting all of that up in seperate objects will help that alot (and save you alot of rendering when you're outside and dont see the inside)

thing is, iv you keep your base one thing.. when you look at it from the outside, you'll also render the inside, and thus the lights that are inside affecting the inside (but being rendered on the entire thing so the outside as well)