Well, having a square texture image isn't working for the walls (it worked fine for the doors, but not the walls... strange).
What I'm trying to do is make a drop-in replacement for this:
using this texture:
And wind up with something like this (note the precise dimensions/locations for the texture corners, these have to be exact so the pieces fit together properly):
So, I can get the size/corners right so that all the puzzle pieces fit together, but can't figure out how to stop the bricks in the wall from getting crooked.