The floor repair goes well. I have created much more work for myself than necessary, but I'll chalk it up to needed training.
Here's a couple pics of the progress. You can see I still have much to do, but it's coming along.
Another part of this process is removing the old asphalt-based undercoating. My intention is to recoat the underside with something prettier, more durable and easier to work with. Removal of this stuff is a certifiable bitch.
Here you can see some of the mess. I've sprayed a liberal layer of Easy Off cold oven cleaner, which does have some small effect on the undercoating. Aircraft stripper works OK, but is far more expensive. I've also resorted to heating a scraper with a propane torch and melting the stuff off. You have to be careful doing that, because the undercoating is dramatically flammable.