After fleeing the mob at the Bubble Boy's house, on the way to the cabin, firetrucks are seen passing George, Susan, Jerry and Elaine. Somehow they all arrive at the cabin before the fire truck gets there, even though the fire truck passed them on the highway.
On the drive up to the cabin, the back seat of the car is full. You cannot see out the back window. After leaving the Bubble Boy's house, fire trucks pass the cars. The shot of Jerry and Elaine in the car shows the back seat empty and the light of the firetruck visible behind them.
In an earlier episode, Susan gives George one box of Cuban cigars, in this episode, Kramer is seen carrying several boxes.
Jerry (Jerry Seinfeld) opens a bottle of water after taking Naomi (Jessica Lundy) home. During their conversation we can see that the cork is on, but then it's off when we cut to a reverse angle of the same scene.
When Jerry (Jerry Seinfeld) confronts George (Jason Alexander) about the answering machine message he left, in one shot we see Jerry with his arms hanging down, but then in the next shot, his hands are on his hips.
While George is wrestling with the bubble boy, he pulls him forward and for a moment the top of the actor's head can be seen, distinctly outside of a bubble.
When Naomi (Jessica Lundy) calls Jerry's (Jerry Seinfeld) apartment to tell him that she's changed her mind about going to the cabin, Kramer (Michael Richards) answers the phone without pulling the antenna out on the cordless phone.
Jerry has a piece of paper with directions to the Bubble Boy's house that Susan is looking at. Later when Kramer finds the paper on the counter in Jerry's apartment, the directions are to the cabin.
We see Elaine (Julia Louis-Dreyfus) eating a broiled chicken in the diner when she has previously said that fish is the only animal she will eat.
It is well established that Jerry has a car phone so George could just call him on his car phone from the bubble-boy's house to give them directions.
When George plays the Bubble Boy in Trivial Pursuit, the Bubble Boy moves his piece to a place on the rim of the wheel on the board and announces, "For the game." In Trivial Pursuit one wins by moving to the /center/ of the board and answering a question, not the rim. However, in the edition dubbed into Spanish, the character says that he goes for the "quesito" (name that is traditionally given in Spain to each of the pieces that must be won to complete the game), correcting the error of the original version.