In these situations, you're talking major work. But the work is more messy than difficult. A wallpaper steamer is basically a hot plate that's attached to a hose that's attached to a hot water reservoir that heats the water and directs steam to the hot plate. For most ordinary wallpaper removal jobs, all you need is a dropcloth, a perforator, a bucket of water, a paint roller, and a scraper. The idea is to score the paper with holes or slits and then apply moisture to break down the adhesive.
Water is a key reason that so much preparation work is necessary before removing wallpaper.
Protect the floor and molding from water damage with pretaped plastic dropcloths taped to the top of the baseboard floor molding. Stick these cloths around the perimeter of the room and then unfold them into the room to cover the floor. This tool looks like a putty knife but has a slot for replaceable blades so you can always have a sharp edge. A paper scraper is a nifty gadget for removing wallpaper from walls made of wallboard or gypsum drywall. It has a round knoblike handle attached to a scraping blade that doesn't damage the paper face of the wallboard the way a sharp razor knife does.