The short story is that Bernie should work, but the process is a bit circuitous.  At the end of all this, Bernie running GS/OS 6 could not read my disk.  It could read an 800k HFS floppy (shocker) but it couldn't format it to ProDOS.  Given that the Mac SE can (I know) format ProDOS, and I assume read ProDOS then, I'm guessing the Printshop disk is just damaged or corrupt.  I mean I guess the other short story is that given the older Mac ability to read and write ProDOS, this was all basically irrelevant except to confirm that the disk is screwed.

Silver lining, I suppose, is that if you have a machine whose File Exchange does not support ProDOS but which does support Bernie and has a Superdrive, you can read ProDOS disks through Bernie.  I gather the 'Write Protection' error I get in trying to initialize disks means you can't write to any disks - but I could be wrong.