I have not done the show Horton's Foote's Trip so I'm not sure what the set needs to look like. But I have designed sets for other Theatres, that had 2 Acts with 12 scenes for Act 1 & 7 scenes for Act 2. The flats that I used were 1/2" Gatorboard Foamcore with special feet to hold the 4' x 8' panel. The Gatorboard is very strong and will not bend over. We painted Crown,Chair Rail & Picture Frame molding on one side for one scene, then the same panels were painted on the back side for another scene. So at scene change the panels had to be just turned around and you have your next scene. You can build the framed flats for less, but you have more labor time involed. With the 1/2 Gatorboard you just put into the foot and then you can start painting. You will have to use the 1/2 Gatorboard for it to stand up with out bowing over. Plan foamcore with not hold up stright. Plus plan foamcore will dent very easy. I have designs and made feet for these panels that will change out after show is over.