Mid bath shower ideas

I recently bought a 1985 Excella 31. It is in very nice condition, no leaks, solid floor, well taken care of. The only interior I dont like is The original twin matresses, original drapes, and most of all the shower. Pan is old, discolored but solid. Walls are the vinyl wall paper. I am looking for ideas. I definetly wood like to do the walls. What material have you used? Is it possible to chang pan without taking out walls.