Revealing mistake: When the sheriff is going to whip Sarah, he tells her to take down her drawers. Bad editing, you see her hand reach back and make the motion as if she is pulling down her panties but it is visible they are still up.
Continuity mistake: The Sherman gets stuck just before the Tennessee state line. Right after Buelton announces that Zack, Billy and Sarah can sweat out the afternoon sun inside the tank, the scene changes to a view of a bright sun in a blue and cloudless sky. Before and after that, though, the sky is thoroughly overcast, with no break in the cloud cover to let the sun through in the first place.