I'm not sure if the OP is reading this anymore, but I did want to offer advice. I've been scraping (and scraping and scraping, you get the idea) wallpaper for so long. We're in the process of redoing my daughter's room and there were many many layers of wallpaper on the walls. I assumed the layers started in the 1930's, but on one wall, they put sheetrock over the plasterwall. It's some bizarre cardboard-like substance, so I guess in the 1950's- late 60's they just redecorated a lot. Anyway, long story shortened, when I got to the last layer on that cardbaord wall, it's stuck like glue over it. I got off all I could, scrubbed it, and my husband put a layer of plaster over the whole thing and it's now smooth as glass. I don't think this would work with many many layers, but my father in law has done this in the past, and after 20 years all is still good. I wouldn't recommend doing this in the more public areas of the home, but in the bedrooms it might work for you. It sounds like from your post that you are a thoughtful remodeler. I, like so many on this forum, cringe when thinking of "flippers" and the lack of care for history that many have. However, there are people who remodel who do a great job and do it not only to make money, but to improve their community. Those people are to be commended, because their vision helps create a longer history for that house in that community. I hope that you are able to bring that home to its former glory and find a family to love it.

Columbusguy, I will try to remember to take a pic and post it when we close on the house next week. The birds match the turquoise toilet, tub, and sink very nicely. The birds may be allowed to stay, at least for a while, but the turquoise toilet is frightening. Wondering about glazing the tub... As for my mom, you are right it is my house and ultimately I will make the decisions. Problem is, I need her help with things like painting and landscaping. Or at least I need her to watch my two little ones so I can do those things. The infant isn't great an entertaining herself and the toddler gets into EVERYTHING. My mom actually tried to talk me into a ranch, but like you, I have NO interest. I love old houses with all their quirks and just want to make sure I'm not doing this poor old place a disservice. It's really helpful for me to be able to send my mom things like posts from this forum to back up what I'm telling her. Mothers always think they know better than their daughters, no matter that the daughters have daughters of their own. :)

You want the base materials to be slight thinner tan the finished.surface. I would just use 1/2 in drywall and EasySand to make up the1/4 inch. This layers of regular premixed mud put a lot of water into the substrate, and then shrink horribly as they dry. If you mix EasySand about as thick as peanut bitter it has very little shrinkage and you can fill that area in mostly one coat with a finish coat (or two) to smooth it off. If you use Easysand20 you can easily get in two coats per day. It does not have to be dry for the next coat, just set. Put a blob aside and when that is set put the next coat on.

Unfortunately, you do not really have an easy task on your hands there. I've done this numerous times since I renovate old houses. Without seeing exactly how deep the grooves are, there a possibly 3 options: 1-install smallish sheetrock over the ceiling plaster (3/8"). I don't like to do this b/c it is usually hard to hang as you have to make sure you get a stud and not screw into plaster or lathing. And, sometimes it is not really level. To save on removing plaster, I just had an idea but have never done. You could run 1x4 wood furr strips across the ceiling, then run sheetrock. 2-You can do the same for the walls, but then the reveal around the doors and windows is messed up and does not look good. Can work if you have really thick trim and use thin sheetrock. But, sometimes this is wavy. 3-Remove the plaster and sheetrock. Best approach. Then you can open a bit of a can of worms: studs that need to be replaced, need furr strips, maybe new wiring... Will look great when done, though. 4-You can apply a wide fiberglass mesh to the entire wall and mud it in. Use hot mud on the first coat---very important! They come 3-4 ft wide. It is kind of expensive, but less than demo. However, if the grooves are too thick then this may not work since the finishers would have to apply way too much mud to fill it in. Julie