Wow! That looks like quite an undertaking. I understand all the blue lines, but am unclear about the black hole at the end of the hallway.
You didn't answer his question?
I to would like to know what the black hole is?
Mountain?
Lake area?
Laundry shoot to the basement?
Furnace sitting there?
Access hole? (Though you don't need one there)
Or for a star war scene your adding to the layout?:laugh:
What's the black hole for?
Edit......,
Sorry, I just went back and looked it now says access hole, lol, all that writing for nothing.:laugh:
You could add a mountain over it just make it so you could lift it out when you need to get in the hole.
I think you could get three loops in the area. Though over by the door the 33'x25' would just have to be some kind of siding or something.
How about instead of the black hole

you just cut out that corner that sticks out into the room. You wouldn't need the hole then.