Water damage

Voyager

my used camper came with the back stained from some undisclosed water damage. We don’t know where the leak came from as it was resolved when we purchased it. It is dry, no smell. I have seen other posts with images that look exactly like my camper. I know it is just cosmetics but, has anyone replaced that panel? Was it a DIY or professionally done? Was it expensive? Has anyone painted it over and, if so, does it look good? I also thought about gluing vinyl flooring.

Thank you all