I most likely won't furnish all the rooms fully, maybe just add things like sinks, toilets, showers, etc. Things that should be there when you move in.
I should have no problem building the structure to the size though. That, imo, will be the easiest part of it. Making, probably about 50+, unique rooms, on my own, will be the killer.
We will see though. Maybe I won't be lazy and completely furnish this thing from top to bottom.