I have wallpaper in one room, the bathroom, on one wall. I am going to replace the drywall instead of removing the wallpaper. Heck, the wall is 40+ years old, time for a replacement!
It will be cheaper and easier and calmer to replace the wall rather than deal with the wallpaper. Plus, I am getting rid of the soffit on that wall, and it will tear the wall up immensely. I am sure of it.
Wallpaper WILL come off, even if it has been painted over......it may take some time (and a little mess), but it will come off.
The most stubborn wallpaper removal job I've encountered was in a 50 y/o house that we remodelled. I ended up mixing fabric softener with water, and sponging it on the walls every few hours for a couple of days. Eventually the water mixture will penetrate the surface and release the paste holding it to the wall, and when that happens it basically just falls off. Stubborn spots come off with another soaking, and scraping with a three-inch putty knife. You can also mix up the hot water and fabric softener in an old spray bottle (like Windex), and spray it on rather than sponging.
You can accelerate the process by renting a "steamer", which is a device that mixes similar chemicals and applies it as steam to penetrate quickly.
Either of these methods are a hell of a lot less expensive than hanging new drywall over it........
doc