Yes and No.
WBCCI does a lot of caravans to and rallies in Alaska and Canada, but not many to Mexico.
Link to 2002 WBCCI Caravan/Rally Schedule
Airstream Corporate also offers caravans. I have a good friend in WBCCI who works on the corporate caravans, and he has gone to both Mexico and Alaska many times for them.
Link to Airstream Corporate caravan schedule