I though of doing something similar as i wanted a trailer that could haul my car or toys plus camp in. I already had a 3/4t Ram to tow with.
I ended up going the easy route and bought a Work and Play Toy Hauler. I can fit 2 RZR or my car in it. Bed is on a lift, the dinette and couch flip up against the wall and both make into beds. Has full kitchen and full bath. 21' of garage. The barracuda tucked away in it now.
Good luck with your conversion!