Teardrops n Tiny Travel Trailers

My father-in-law is helping me build my trailer so we brainstorm while we put things together. We need info on how to accomplish the below.

Our idea is to put a piece of 3/4" plywood on the top of the trailer as the floor, then flip the trailer over and put that extruded (styrofoam-like) insulation in the space made by the metal beams of the HF 1800# trailer we are using. Any ideas, anyone do this???

Also, what would the pro's/cons be of cutting 1/4" plywood to cap the opposite side (bottom) of the trailer? This would be like using the frame of the HF trailer as the 2X2 floor joists. It'd keep from eating up any space inside the trailer (height-wise) other than the 3/4" plywood.

Anyone do this?

Eric,
Read Cary's comments in the thread about sidewall wall constuction in this section. He's got some good info on insulation.

Well, I am forego-ing floor insulation as I won't see any cold camping trips anyhow. Just gonna us 3/4" flooring. May come back later and add rigid extruded foam later and roofing-coat it in if needed.

If you have a mattress in there it is like installing floor insulation, it may not be needed

I was going to put down a peice of ply wood, put down 1x1's is a square pattern and put insulation in them and ad another piece of ply on that. I recently found another methood though. I am going to skin in the trailer frame with a sheet of plywood, and put another piece on as the floor, I would seal it good when doing this. Then drill a hole and add a 2 part expandible foam in it. This would make a 3-4 inch thick peice of foam insulation. The only non insulated space would be the foot well that is not to big. bye