Hijack away! You're sticking to topic, regardless of how much your topic and mine are diverging...
You're enjoying the "road less traveled"!
As for material choice, I'm soooo at home with composite structures that your suggestions seem like daunting tasks in comparison (but I'll bet you don't have a 6'x20' vacuum table for making up panels!) I like the variety of means to ends I find out in the BBS world - I learn a little something almost every time someone takes the time to type it out, even if sometimes it takes me five readings to make it sink in to my skull.
Typically I'll use PVC in two ways - either as a very well controlled slightly flexible (pipe) mold surface for rounded sections or as easily fabricated light (foamed PVC) sheet goods, though often I'll use polypropylene honeycomb sheet faced with fiberglass as a lighter alternative. Laminating three 1/4" layers of honeycomb under vacuum over a PVC pipe mandrel makes for a very light and rigid curved section that bonds very well into flat and curved panel sections to make up a stiff monococque structure, removing the need for a separate frame for the trailer, significantly reducing weight and complexity. I use pultruded fiberglass sections as edge stiffeners and fastener rails in the lower part of the trailer structure.
The sail-like Conestoga top will be getting a representation on this trailer, as the planned side-shade tunnels. I don't like having "stuff" sitting in the boundary layer, so I'll be building pockets into the solar panel fairings to accept battens for a curved side-shade "porch" like all good RVs seem to have. This one will be more durable than most seem to be - I am trying to find a source for remnant Tenara cloth.
