So, went ahead and got the new battery in the car. Hooked up the positive side and used the multi-meter to connect to ground (YouTube video said that was safer than going through the positive side). Anyway, got a 1.0amp draw. Started pulling fuses, and when I pulled the "backup" fuse the draw went to almost nothing.
Looking it up, that appears to be a memory backup circuit, and has nothing to do with reverse gear. From my reading if I pull it I'd lose some functions, like mpg readout, possibly radio (or maybe just presets) and a few lights. But I think the car will otherwise work. Going to try that, and if it runs, I can at least take my time finding the problem with the parasite load location.
