The first thing I started on once getting the frame is to strip the pressure treated board off of the frame. I saved the boards and used them to make the back door. Once stripped, I used some oil based paint and painted the frame.
Next, I had to get some lumber and plywood. So I posted some items on Craigslist and within a few days, I had 12 sheets of 1/2'' plywood and enough 2x2's to start building. I traded a new toilet and a gas burner for all of the lumber, yet, not costing anything to build so far. Well, besides the car I traded and the wood screws. I then framed up the floor and painted underneath the floor that will take the brunt of the weather.
I used gloss black for the undercarriage. I framed the floor in 3 pieces to make it easier for me to assemble.
I used self-tapping 2'' screws to connect the floor to the frame.
On the center piece I attached the center framing to the metal frame first.