When the campers reach the campsite, Caroline is throwing off her bonnet to drink water. In the next shot she is wearing it again and throwing it off to give Carry a drink.
The campers are due to set-out at 6am, according to Charles but the short shadows and quality of light suggest it was around mid day or later when the scene was shot.
When Nels picks up Mrs. Oleson's tea service bag he is carrying it out of the stream bank. The next time we see them Mrs. Oleson is far ahead of him on the trail and carrying the bag.
When Laura and Nellie start walking back to camp after getting out of the river, they are covered in dirt. When they arrive back and reunite with their mothers, they are clean.
When the 2 girls get out of the river, both their dresses and hair are soaked and muddy. When their fathers find them and bring them to their mothers, their hair is dry and the dresses are dry and clean also.
When Nellie and Laura are floating down the river, you can see the rope that ties the branches together.
When Laura is trying to get Nellie out of the river while Nellie is fighting her, Laura says, "fine stay there," and you hear Nellie say "Don't leave me!" but Nellie is just standing there panting and her lips don't move.
When Nellie and Laura are in the water hanging onto the branch, Laura is yelling at Nellie to kick and Nellie is wailing and yelling she can't. Neither girls' mouth moves during the exchange.
When Mr. Ingalls and Mr. Oleson are looking for Laura and Nellie on the river there is a crew member on the right side of the screen in the debris who "pops" up.
When Laura and Nellie are climbing out of the river, after their adventurous ride, and Laura is trying to pull Nellie out, Laura's dress billows up in the water, and Melissa Gilbert's shiny, black wet-suit is visible.
Poor is the teacher who sends kids off to collect leaves without first warning them about poison ivy, poison oak, or poison sumac.