It was a combination of things.
Rust, plus lots and lots of gunk on the adjuster. Where I thought I'd backed the adjuster off, turned out to be just a jammed adjuster.
Solution: Cut a hole in the drum, and find this out, then unjam the adjuster and got the drum off pretty easily.
Then found that I need that axle jig after all. I see no way to press this baby off without it.
So much for a quick, easy repair.
Baby Beast 2- 1999 4Runner SR5
Baby Beast -1987 4Runner SR5-Gone, but not forgotten