Has anyone reclassified to 91B at Ft. Hood and gone to the Regional Maintenance Training Center?

It sounds like you have a lot of misconceptions about Reclass.

This is how Reclass on active duty works:
1. You request Reclass through your career counselor.
2. You extend/reenlist for the class if you don't have enough time.
3. 90 days prior to class you come down on assignment instructions. If it's PCS length that's where you orders go to. Otherwise, it's TDY enroute.
4. You reenlist/extend for your follow on assignment if you haven't already.
5. Levy section cuts your orders.

You aren't eligible to request a Reclass until you've been on station one year. That's in accordance with AR 614-200.
You won't go to any school house other than the normal one at Lee. The other AITs around the country are for reserve components.
The only way for you to stay on post is if your unit pays for your training. The TDY and return has to be requested at the same time as the Reclass request. Unless you're so special that you're brigade is willing to fund your training when they could get another mechanic for free by waiting - you're going TDY enroute when/if you Reclass.

I hope that answers your questions.