After reading your posts detailing all the features of the Castle, I have to ask:
How in the world do you come up with all the details so fast? It's amazing how creative you poet types are:-).
The details are already made up. The best map of the Flying Castle is the one inside my head.
Besides being a poet, I also style myself as a science fiction writer. Many of the original castle details came from my second book.
There are actually four areas. The Thrust Ring is a large diameter circle of approximately square cross section. It has two support arms reaching from the inside of the ring out to the Flying Castle. (An "elbow" joint bends around the ring.)
Two other support arms reach out from the outside of the ring to support the Habitats A and B. They also have stabilizing cables.
Inside these capacious arms are electrical conduits, miles of support plumbing and gas lines of various types, and the spherical elevator tubes which afford passage between the Habitats. They function like subway tunnels. (That's part of the reason they're dangerous.)