RE: Backstage Set
Well, it'll have to be in the air anyhow, because there are stairs that go down to the stage entrance in the back, plus a door on the left and right (the one on the right is Pop's box). Right?
Forgot to mention, just hallowed-out plastic, like underneath Animal's bandstand. It could also allow them to put in a trap door or two underneath the backstage area and onstage if it's a few inches in the air.