Well, XANADU is a One-acter but the rights for it haven't been released yet.
I think Act One of THE APPLE TREE (the strongest of the three) would definitely work as a stand-alone piece for a class (not a full-blown production). It has a small cast, an adorable score, and a very romantic story.
"Some people can thrive and bloom living life in a living room, that's perfect for some people of one hundred and five. But I at least gotta try, when I think of all the sights that I gotta see, all the places I gotta play, all the things that I gotta be at"