Since Mom came over and helped me move the generator out of the bus, I was finally able to finish insulating the floor.
I'm particularly happy with how well this piece around the stairwell worked. It was a single piece of plywood that I measured and cut to fit the space. The other side of the aisle was filled in with the scraps left from this cut. Not as pretty, but works just as well... and that whole section of floor will be covered by cabinets anyway!
I also made a video describing how to create a ceiling template... but didn't hit the "record" button hard enough the first time!
Doh! I'll edit what I reshot and post it later.