Here is the start of my build. Actually got the frame done a few months ago and then had some other projects and life delay the wood portion. It all very exciting to me. I feel I have pretty good design and build plan thanks to all the help and inspiration I have gotten on this site.
Floor is 1/4" Plytanium top and bottom with 3.5"x1" framing that I ripped from standard 2x4. Got the 1" foam board for free from a friend. I used PL3 and #6 1" screws. I needed the wide width so I would reach the gussets I made to bolt it down. I was happily surprised how rigid and strong it is. Heavy too. The wide angle lens makes it look much narrower than it actually is. Batteries are going below in the hole. Made it big enough for 2 100A Lithium although I will initially use deep cycles.