Thanks Guys! Mark the upper level foam has a big hole in the middle so I can stand in it, also I have it free floating right now, so if I have to I can just lift the top right off. But that could change once there are buildings and the airport. I will cover the hole with the runway and be able to just push it up and out of the way!
Bob, the bracing was really needed as I didn't want any legs out near the edge of the layout!