Continuity mistake: In the pot shack scene Dax Shepard is holding the package of pot to his side, you see him slowly move it behind his back to hide it from the two hillbillies. In the next scene, after they flash back from the hillbillies, it's back at his side and he's once again slowly moving it to his back. Shepard, and the other cast, admit this is a mistake in the commentary.
Continuity mistake: Near the end, when Tom, Jerry, and Dan are about to be shot by the two hillbillies and the cop, there is a brief scene that shows all three guns being loaded from a side view. The gun closest to the camera is a handgun. When the camera zooms out, all three men have rifles. There is no handgun to be seen.
Continuity mistake: The 3 guys have just gone through some heavy rapids. As the rapids slowed two of them are on top of the canoe. They call out for Tom and then again for Tommy. Between the two call outs the shot changes. In the first shot the river is still flowing swiftly. During the next shot when Tommy is called and found under the canoe, the river is at a stand still. This scene was filmed in 2 different parts of the river.
Continuity mistake: When the guys are in the tree house right after Dan tells the girls about using the pussy willow reeds you can see Tom just about to take a drink from a canteen, then maybe a second later in the very next shot it shows Jerry taking the canteen from Dan and passing it on around the circle.
Continuity mistake: When Matthew Lillard is talking about not having responsibility and that surfing is what he loves while the guys are by the camp fire, his sweat jacket is unzipped in one shot as he lays back. The next shot it is zipped up completely. After he stands up the zipper is now unzipped halfway down his sweat jacket.
Continuity mistake: While up in the Fort Cooper tree house, after the three friends get their treasured possessions back, Dan reaches down to pick up a mix tape with the DJ intros on it. When he picks it up, C-3PO is still in his right hand, but from a different angle C-3PO is not in his hand with the mix tape. There is not enough time for him to put C-3PO down. Then after Jerry unfolds the map, Dan doesn't have the mix tape in his hands.