I am not asking to build the Stunt Show, but I have a recommendation for anyone who would want to do it in their room for VMGM.
Instead of using the Herbie Car for the whole show, use it for only the Disney regular segment.. May I suggest also to put two Herbie Cars together, so when they split in half, you can move the two pieces. As for the Drivers, I would use people in Herbie Costumes, riding on Everest Tracks. In the WDW version of the ride, it takes a while between set breaks to get set up..
That is the time when you lay out the spare Everest Tracks. This way, you control all of the action, and to make sure that they do not get off of their car. As for the water pit in the scene, use a Water Trough. Then, when they are riding their waterskis in the real version, you could use river pieces.
As for the final scene, I am not really sure what to do for the fire.. Maybe a Ring of Fire would come out in Villians Month, celebrating Jafar or Chernabog..