What's the best way to temporarily attach buildings and whatnot for easy maintenance?

I'm working on a diorama that my model railroad club will show off at train shows. Because it will travel, everything on it needs to be sturdy and able to be handled. However, because I will need to do maintenance on it, I'll need to be able to remove buildings and whatnot to access the internals.

My thought is that I would use hot glue for the parts I'm still working on, but my worry is that when the module is being stored in the club trailer the glue will soften and melt.

Anyone have any ideas?