Retiring an old travel trailer into utility trailer

I really doubt the flimsy body on this trailer was adding much to it structural rigidity, but I do plan on welding in several crossmembers from left to right along the lines of the frame before laying down my plywood. The camper is about 7 feet wide but frame about 5 feet wide. So I will also need to fabricate some homemade fender mounts for both tires. Thank you all for the opinions