When Huck Finn is walking with Billy Grangerford (at 45:05 to 45:07) to a brick outbuilding where a new slave is chained, you can see the brake lights of a blue mini van in the bottom left quarter of the screen - look to the left of the tree trunk, under the shrubbery.
Huck's raft is rammed (at around 49 mins) by a ship with a high bow, designed for rough/open seas. But when the camera angle changes, we see a typical Mississippi paddle steamer with the characteristically low bow, steaming by the wreckage.
When Pap Finn is carrying Huck over his shoulder, down the stairs, we see (at around 5 mins) looking down from the second floor that the stair landing has a 2-candle sconce on its right wall and its left wall. At 12:11 looking up from the first floor there is no sconce on the right wall of the landing.
When Huck's father is carrying Huck out of the bedroom over his shoulder (at 11:51 to 12:01), you can see a sprinkler head on the ceiling of the hallway. The DVD resolution is inadequate to differentiate between its being a sprinkler head or a capped-off gas light pipe protruding down from a round base.