Brandon only had one pair of shoes with him, the tennis shoes he was wearing. Brenda accidentally left his hiking boots at home. When Brandon falls over the edge of a cliff, he loses a shoe and it drops down to the bottom of the canyon. Then when they are all getting into the van to leave, he's wearing both shoes.
The pair of sneakers that Brandon is wearing at the end of the episode are different from the ones that he was wearing when he fell.
I the scene where Brenda chases after Dillon, they end up at the vending machines where they see a new bride. When her husband joins her you can see the boom mic at the top of the screen.
When Donna, Steve and David are leaving the cabin to get some beer and the camera switches to Brandon and Brenda talking, the boom mic briefly appears from the top of the screen.