Revealing mistake: In the overhead view of the bus driving across the desert to Camp Greenlake the dust behind the bus is CG, and near the end of the scene the bus moves up in the frame and the end of the dust trail cuts off with a straight line.
Revealing mistake: After Kate Barlow leaves the sheriff's office she runs down the road and past the store selling guns and powder. The words are backwards, showing the shot is flipped.
Answer: He's eating a candy 'fruit' wedge. I remember him holding them when Stanley is first shown into his tent so I assume that he confiscated them from Stanley.