Today I found some time to get to the lumber yard and get the plywood and cross braces. I'm using 3/4" plywood for the sides and 1x4s for the cross braces. I'll cut the roof curve into one of the sides of the cross braces to create the required shape once things start moving. Because we are fair weather campers and I'm trying to keep costs down, I'm not going to be using any rigid foam. I may have to add another one or two cross braces to support the roof skin, but that's no big deal. I also fou...