Here's the finished piece I started yesterday. The edges have been covered with a strip of thin black card and hot glued in place.
I really like the finished product.
We got to try some of them out last night (without the cladding) and we agreed they were a step up from the original efforts. You may note that there are a few wisps of hot glue around the edge. I will either paint over them or trim them, or a combination.
If I were going to make even better floor plans like this I would seek out thicker foam, but the thin stuff is cheap and easy to find.