A guy tried this with one where I camp sort of regular, he didn’t want to spend the money for new canvas. He used 3/8 plywood and 2X2′s. He got the sides looking fairly good but never did get the slide-out beds figured out. He wanted the beds to slide. I suppose the beds could be boxed in solid if it wasn’t to be taken off of the campground. He gave up and junked it after about 3 months.
A guy tried this with one where I camp sort of regular, he didn’t want to spend the money for new canvas. He used 3/8 plywood and 2X2′s. He got the sides looking fairly good but never did get the slide-out beds figured out. He wanted the beds to slide. I suppose the beds could be boxed in solid if it wasn’t to be taken off of the campground. He gave up and junked it after about 3 months.