After posting Post I yesterday, I spent a little time starting to sand. Even with the damage, that finish is tough; after around 45 minutes I'd taken a lot of surface off but was nowhere near the wood.
Idea occurred, to try today: scraper. I wondered if one with a nice, sharp hook would be able to shave the old finish off more efficiently and still not bite into the wood. So after got home this evening(busy and fairly productive day) and all the livestock was fed, I took one, rolled a hook onto one long and one short side and gave it a try. It did indeed shave some finish off, but it was still going to take a while. Then took it over a spot where I'd picked off a piece of the separated, bubbled finish yesterday*, and a couple of big flakes popped off.
That was surprising, so stopped and studied things a moment, and discovered something: I could ease the hook up to the finish, carefully pushing down just enough to let the hook grab the edge of the finish, and pull. Pop, and another piece or pieces of finish would come off. Without leaving a mark on the wood that I could see.
Put it this way: instead of the several hours of sanding I'd (hoped)figured it would take to clean the back, in about twenty minutes I had the back clean, not a flake of finish left. Spent a couple of minutes with a sanding block and 220-grit paper, just to check the surface, and it looks good. If this works as well on the other surfaces, it's going to save a LOT of time.
I have no idea if it would work this way/well on a good finish that was just scratched or otherwise needing repair(it would definitely work to shave the finish down some); it may simply be that the way this finish was coming loose in places allowed the scraper to take it off this way. Either way, it works.
*using one of those 'You have been pre-approved!' fake credit cards to pop it off