In the beginning of the episode, when Gary is using the fire extinguisher, the way that Gary is holding the extinguisher changes. In the exterior shots, the tank is vertical. When viewed from inside the trailer, the tank is horizontal.
Towards the end of the episode, when Gary's father is talking to the woman's father, there's a train passing behind Gary's father. It goes from stretching across the screen to completely gone. The tail end of the train is then visible before it disappears again.