printer weirdness
Tonight I was able to mostly characterize it, and it's weird: after the first page prints, the printer will stay in that state until I go to some other application (I used TextEdit) and initiate a print, at which point it becomes unstuck and gives me my next page. (I do not need to actually print from TextEdit; once the printer wakes up I can cancel.) Iterate until done. I'm 99% sure I've printed from this configuration of Trope Trainer before, though there's been an HP driver update since then. No other apps seem to be adversely affected.
Now that I have a workaround I can just chalk it up to random weirdness, at least until I get annoyed enough by HP-Mac incompatibilities to go buy another printer. But my hardware seems intent on keeping me on my toes.