Your choice of wall coverings is a personal one and totally up to you. Your best bet would be to check out an RV sales center and ask. I've seen virtually all types of wall coverings used over the years. I like wood paneling but not the cheap stuff like you may have remembered from a late 60's basement remodeling job. The look today is more that of a luxury upscale executive office or even that of a library in a Victorian mansion. Decide on the look that you want and then go to a paneling store where the choices are very, very extensive. You won't get that in a box store. There is a wide range of patterns of wood look as well as that of a wall paper look. The material is a Masonite like product with a vinyl textured top surface which is very easy to put up and also to take care of. Real wood paneling or even actual bead board or v-groove tongue and groove boards are more expensive, heavier, and harder to put up but it is the real thing. I've seen the full range of all these coverings on new units at large RV centers. I like crown molding but again that can be difficult as the corners require a complex double miter cut unless you use pre-made decorative corner blocks. They look nice and are very easy to put up. All your cuts are right angles and can be done with simple tools. Be sure to use good indoor outdoor construction adhesive to install it. You don't want any squeaks or rattles. Indoor panel adhesive isn't song enough and may not be able to withstand the huge variations in temperatures that your parked motorhome might have to endure.