I don't have anything photo-worthy to report, but today I did spend several hours getting the worst of the filth off the bare floor of our little house. We're getting ready to put in a new subfloor - and I can't wait, because it'll be awfully nice to be able to walk around in there without hopping from board to board - but since the camper has been sitting stripped and not very well sealed for years there was a thick layer of dirt on the floor. I tossed in a couple of plywood pads to take my weight, then scrubbed down the entire floor with Simple Green and a scrub brush.
The next step is scraping to get out as much as we can of the residue from the original subfloor. Most of it is gone but there are still some shards of OSB and some glue. We also noticed a previously-undiscovered hole in the bottom of the shell that we'll reinforce before going any further. We'll want as smooth and clean a surface as we can manage before we put down the new floor. There are large gaps around the windows since the carpet has been removed, so I taped over the windows and vents on the outside to keep the camper from getting so dirty again.
It looks like the hot water heater is a dead loss - someone left it with water in it, I have no idea how many years ago, and it's completely rusted out. While we're working on the integrity of the shell and chassis, I'm going to look into the feasibility of replacing that old heater with a tankless one.
Overall we're making slow progress, but you can probably expect the Casita to be put on the back burner for awhile soon. We just ordered 1700+ square feet of laminate flooring, and getting that installed in our house is going to be the number one project for awhile!