Why skim coat? Please,please please, do NOT paint over the wall paper, that would be a horrible mistake, considering how easy it is to remove. The room you have already stripped, apply a coat of Gardz, let it dry, sand smooth clean, apply a coat of tinted primer and 2 coats paint, done.

Hi Christophern - the texture of the plaster is very "sandy", and in addition to the crazing, has some noticeable trowel marks. I don't think primer and sanding alone will be enough to get things smooth enough for paint.

Those are only drying cracks, and don't pose a threat to the integrity of the plaster. What you need is a real plasterer to put on a white coat with lime & gauging.
Casey

We too had bad wallpaper covering plaster in our entire house. In one room, the wallpaper was a "pre-pasted" removable kind and came off easily. It would have been dumb to paint over this paper because it was so easy to remove. However, in all the other rooms, the wallpaper was VERY difficult to remove because it was the old variety that came off only in one inch strips. We got several quotes from professionals who refused to touch the wallpaper. At least one professional recommended that we paint the wallpaper. We then tried three different solutions.
First, my husband removed the flocked wallpaper in one room. It was very difficult to remove because it was not "removeable" wallpaper but older, heavily pasted paper. He tried every tool for removal, including steaming, scoring, etc. The only tool that worked was a 4 inch razor blade scraper (not 3 in or 5 in according to him!). That was a long process and the walls were in such poor shape that we had to wallpaper over the plaster when we were done.
Second Approach: In two other rooms we painted over the wallpaper. In one room, a bedroom, the paint looked great. The painted wallpaper has held up fine for 20 years. Just last year we painted it again with no problems. The second room where we painted over wallpaper was the bathroom. It bothered me to paint the wallpaper in this room because it was poorly wallpapered in the first place. There were several corners where the wallpaper was not flush with the corners, but "wrinkled", for lack of a better term. Because every inch of the room, including the ceiling, was covered with wallpaper, we just painted it. It too has lasted 20 years, but it does not look as good. The paint made the wrinkles more obvious to me. Also, we must have had a leak, because the wallpaper on the ceiling is beginning to bulge. It will have to be redone soon. I am not sure any outsider would have noticed the flaws in this room, but I did. It was a second floor bath, though, so I just lived with it.
Third approach: In our dining room, I think we again stripped the wallpaper, but then my husband attempted to plaster the walls himself. BAD IDEA. Although he is very handy, this was a job that he could never get to look good, no matter how many coats he used and how many times he sanded it. (By the way, the sanding made the entire house a mess!) After weeks of trying , he finally gave up. Instead of hiring a professional plasterer, he applied a special wallpaper that was meant to be painted. This wallpaper was like canvas and smoothed out any irregularities and made the wall ready for paint. It still looks great. My advice to you would be to look into the cost of hiring a professional to either plaster or apply the coat of the substance named above and sand it. I am not sure if we ever got a quote for plastering and sanding. If it is cost prohibitive, get the wallpaper that is intended to be used on plaster walls and then paint it.

Thanks @sombreiul and @enrightm, extremely helpful info. I think we'll just hold off on doing the massive whole-house wallpaper strip for now and focus on a couple rooms at a time.