This afternoon I built the other wall, put a door in with a small window and got it painted.
All that's left now is paint the bottom of each floor piece, then fit the canvas.
I think it's going to be fairly hefty, probably about 80lbs so far.
The canvass is pretty heavy, so it will probably be well over 100lbs. I beefed up the door wall to keep it from being too flimsy.