[3drburb]

I don't know if all the frame pieces are available so if I were in your position, I would take a lot of measurements and go a local wrecking yard or find someone parting out a pickup and get as much frame and braces as needed and only remove metal as I have a piece next to me to replace it with and what is not available, just remember it only metal, so brace can easily be made as long as you can bolt the needed parts back to it. Kind of working your way into the rot then working out, to keep everything sturdy.