After the metal sign at the trail intersection for Big Dog.
End Point
At the dirt jeep road. Chugga Chugga Stage 1 - 3 flow and loop into each other.
Directions from Parking to Trail
Park on anywhere on the main road. After you pull into the gate look for the dirt jeep road on your left and start at stage 1. If you want to repeat stage 3 the trail start will be on the left of the main road past the game stand/grill area. You should see a couple of entrances but you want to look for the metal sign on the single track in the trees.