You know, I never heard a title so I'm not sure. It was described to me, but no one mentioned a name.
Apparently Lasseter is a big fan of the really old-school Mickey cartoons (back when the Mouse was cool) and that helped instigate the project. Ultimately the project was a little too "next-gen" for some executives so Disney backed out of it. What I heard sounded awesome, though. And it'd be a nice way to make the characters interesting again.
AFAIK, you are correct - the only tunnel involved in the expansion provided access to Cindy's haus, which is now kaput. In fact, this was where a lot of the big cost savings came from when the plans changed, and allowed for the possibility of more elaborate replacement attractions.