I am building a new one right now for a Cheyenne with Johnny Branch... Just my opinion, but start new and you will be money ahead, plus it will look a ton nicer. Steel is cheap, but the axles, fenders, wheels and tires, etc etc are what add up. None of the existing road trailer parts will work and you would have to completely dissect the road frame to work.....
Just my opinion but sell the road trailer and put it toward new parts.....