I did an "enhance" on the photo, enlarging, straightening, sharpening, brightening, etc.:

Granted it can't actually reveal any detail that wasn't there in your photo, but I've found that it can make it "easier to see" what's there. I was thinking that trying to analyze it might make it easier to spot the playset -- or some part of it -- in a flea market or yard sale or wherever. I have a bunch of questions, which might spur some answers or observations from others:
So it seems that there's a hinge of sorts between Henrietta's house and the castle, where it would fold back and close to contain the accessories. Is there another hinge between the tree and museum-go-round? Maybe the museum folds into the tree, which then folds back to meet the castle?
What are the "20 accessories" that are mentioned? I count the King, Queen, Prince, X, Henrietta, two thrones, a purple riding horse for Tuesday, a telescope, a rocking chair, an airplane, a letter or postcard (in front of Henrietta), and four cards in front of the castle. That's 16...what are the other 4? What is the red object next to the telescope?
What is the thin spiraling column visible inside the castle?
I don't remember the airplane from the show...whose was it?
I'm not sure if the photo is appearing above at full resolution, but I have it posted here as well:
http://www.grundoon.com/mrnombplayset.jpg