As bad luck would have it, I just sold both my "pickle" forks (ball joint forks) a couple months ago after they sat for many years in my tool chest. So that leaves that method out for now.
I like the idea of soaking in PB Blaster. Because the quill is loose, I'm going to try to drop the quill out the bottom of the seat tube. If I can do that I have direct access to the bottom of the alloy stem, sans the quill. I'm going to try that 2X4 prop, then put a driver inside the stem, with the frame on the 2X4s and hit it with a light sledge.