In most versions, while driving the elephant vehicle, if you drive through the Gronda inside the graveyard, the Gronda will freeze and will not react to anything until you get far enough from it. In the PS2 version this will not work, as the wooden elephant will not move past the gates.
In the woods containing the elephant vehicle, there is a small wall you can jump over that leads to outside level boundaries. However, once you jump over to get out, you can't jump over to come back into the level, so you must fluff yourself in order to get out, by using an explosive weapon or falling off the level.
Using Tweek, it is possible to fly over the level boundary by first going to the top of the treehouse, then simply flying over the boundary.