I don't know if it technically counts as a "home," but I'm currently renovating a 1976 Airstream travel trailer and I'm stuck on how to waterproof the bathroom, particularly the shower surround. The trailer is currently in the dry heat of the American West, but will be traveling all over the country, so I'm concerned about preventing mold and rot. The original solution seemed to be some vinyl wallpaper over wood walls, which was peeling off when I acquired the trailer. I have saved the original shower pan (plastic) and can reuse that, but don't know what to do for the walls or floor.

Essentially, my issue is that traditional methods don't seem applicable here. I've seen some people put in tile, but I'm concerned the weight will be too great. Additionally, the movement of the trailer will probably crack the grout and/or the tile. I've seen plastic surrounds in newer trailers, but I haven't found a new one which will work for my bathroom configuration. (The shower sits over the wheel well.)

So, I've been looking at vinyl options, which are lighter, flexible, and waterproof. However, people online voice concerns about using sheet vinyl on walls because of mold growth behind it and about vinyl tiles because they're apparently not rated for vertical applications.

I'd love to replicate a tile look in the bathroom without using actual tile, but at this point I'm not sure it's possible. So, if someone has a miracle solution to my conundrum or cautionary tales about any of these options, I'd love to hear it. Thanks!

TLDR: I need a waterproof, flexible, and lightweight option for a travel trailer shower surround and floor. Tile and plastic surrounds won't work in this situation. Anyone used vinyl?