He, like every other way to the Mosph High, only shows up after the tomb it seems.

Teleported back to town upon reaching the tomb and after putting the bird down.... and he wasnt there. Sped through the tomb, popped out to west gate, and there he was.

Question is... if all 3? ways to get to the Mosph High come open at the same time......

I don't know, it just seems like Wyrm's Nest should let you in sooner than the boat quest, but both become active at the same time.

Hmm... Now I wonder if I should have tried to reach other areas through Z caverns.. or if it would have been blocked off. Or even tried to fight the big thing down there before going to the tomb. Probably is blocked off though.