I don't have experience with switching from private to public, so I won't have advice specific to that. However, can you set up a meeting with the principal instead of getting the runaround from the same person who's been telling you it's the principal's decision?
Good luck. I can relate to the advocacy process taking forever, and taking a lot out of you... We finally got a break a few months ago with DS7's transfer to a school for HG kids that is working out great, but the constant advocacy period began when he was 4. I'm happy there's a break for us now, and hopeful it will continue, but I am prepared for more work in the future just in case.
