I recently purchased a 1950's style Mail Order home. When looking at the home I noticed that there was wallpaper lines under the paint. I thought while a pain, I could get this done. Once purchased I found out that the walls are plywood. No sheet rock. The wallpaper that was painted over looks to be the original pre order paper taht was originally on the walls. With out sheetorcking, how can I smooth these walls out to be painted? Do I just mud every wall? Is there a flat paneling I can buy that can be painted? Thanks for teh help!