Well, maybe not two steps back, but it sure feels like it. I've fiddled with the staircase and the lobby partition wall but I think they are now finished. I filled in the original stairway hole and gave the ceiling a couple coats of white ceiling paint. tonight I finally got up enough nerve to cut the new stairway opening. I measured about four times but still managed to be off enough that it took a little more plastic surgery to get it where it needs to be. The staircase unit slides out as one piece.
I've prepped the rest of the vertical pieces -- flat walls and tower walls. I painted both sides with flat white ceiling paint and then coated the inside surfaces with a skim coat of wallboard mud. I spread it on with a palette knife and like the way it looks. Tomorrow I'll paint it and put some of the walls in place.