i've probably removed more wallpaper than anyone on this continent.
remove top layer of paper if possible.
fill a garden sprayer or commercial chemical sprayer with hot water mixed with Wallpaper removal solution you can find at any paint store.
score gently with a large paper tiger. i've never had a problem. there might be the odd damage produced from pressing too hard,but expect plenty of prep anyways from gouging with a putty knife or bladed scraper. i've used a dull blade for years and i won't ever replace it with a sharp blade. various size putty knives are also used at times.
spray an entire wall with the chemical solution and let it soak in.
come back in 10 minutes and re-wet about 5 feet of the wall (5'x7'=35 sq ft). this is about 1-2 sheets of wallpaper
let soak for a few minutes and start to scrape. often times it comes off in sheets.i remove the baseboards where possible. start from the bottom and work your way up.
after removing 35 sq feet,wash that small section of wall with hot water and tsp. have another rinse bucket of hot water to clean off the tsp residue.
i use a bee style sponge mop to clean my walls.
move on to the next 35 sq feet (1-2 sheets)and repeat process.
the walls will need a good 4-6 hours to dry from the soaking before prep.
if the walls need extensive prep i mud then prime/seal with acrylic primer. if extremely bad i first seal with oil based coverstain,mud,then prime mud with acrylic sealer,then 2 coats finish paint. (extreme cases)
[i'll have to try the sanding method using 40 grit paper in the future. sounds like a good idea.]