Have you considered attaching a clear, heavyweight shower curtain (or some other clear vinyl/plastic) with Velcro to the walls? That way you would still see the original walls (which I am supposing matches the rest of the bathroom?) but they would be protected by the vinyl. The curtain/vinyl can be attached at the top of the wall and cut at the bottom so that it hangs down into the pan. It would probably give you more room in the shower rather than having a shower curtain hung on the rail all around. A number of people who have TrailManors have done this mod and are very happy with it.