Hello, Lonely Poster from 2013!
I wanted to build a tiny-house on wheels since 2013 and only now am doing it. I bought a Harbor Freight trailer, 1,720# bearing load. Nightmare of headaches in missing parts and unknowledgable technical support.
I am reinforcing the frame and adding on structurally to support a larger footprint than the 4' x 8' trailer. I'm an architect and know pretty well my structural concepts.
My issue now: Dumbly thought that I could build all within my garage. Duh... height issue. So, now, I wonder if I should build in sections.... might make future modifications or moving easier....just bolt together and use hurricane straps on roof for strength.
Other option: Build first, then raise onto trailer and bolt into place.
I've decided to use treated lumber for the base framing with steel studs for the walls and roof.
Update on your own project/s.