get a good paper tiger wall paper removal tool, get some remover chemical, get several wide strong putty knives and several spray misters.
What you want to do is to get moisture and solution behind the paper itself, below all that paint. when the paper behind is saturated with moisture and chemical it makes it easier to pull off.
You must break through the paint layers and again,,,,behind the actual wallpaper itself. Be careful not to gouge the drywall and not to pull off that very important drywall outer skin. This skin is what holds paint and texture to the actual rock.
This job will drive you crazy and only work in a small area at a time like a square foot and then move on constantly moisturizin the next area to be worked on. The key is saturation of the layers so they will come off easy.
If this becomes too hard, which it could be, consider re rocking all the walls with 1/4 inch drywall and starting fresh. I have done this and its much easier. You do have issues that can be overcome around the door casing, window casings and floor molding.