Hang Board in a Trailer

Hey Everyone, 

I am trying to set up a hang board in a company trailer that I stay in during the season. It is essentially a 5th wheel, and the walls are rather thing. I have yet to find any kind of stud with a finder and frankly am very unsure it could even hold me. Has anyone had an experience setting up a hang board in a situation like this? I see plenty of threads for vans and apartments, but this thing truly has no solid studs that I can find or think of using. Any ideas how I can get this board set up? I am appreciative of any and all help!

Make your own freestanding frame from 2x4 (or the like) which is supported by the floor and maybe jammed tightly between two of the walls if needed

Trailer construction varies, but in general is very shitty. I’d hang it from a tree or build something freestanding.