Despite all the drinking John and Ruthie do, the amount of booze left in the bottle never goes down.
In the scene where Ruthie is tied up, her hands are bound with smooth silver duct tape or something like it. When John steps up to free her, he reaches for the gag first but the tape is already tattered like he tried to pull it off.
John signs the hotel guest book, then closes it and pushes it back to the manager, but in the next shot it's open and facing him again.
In the first shot after the RV stops, its light falls around one of the suitcases. Over the several shots, this suitcase gradually moves itself out of the pool of light.
Bob drives off from the circle over his own tracks (3-point turn), but in the rotating shot in the morning, his tracks run off in a smooth curve like he simply drove forward in a tight turn.
Just before Cowboy finally opens the bowling bag, the zipper is halfway up the right side. John was warned not to open the bag and was terrified by the potential consequences; he didn't open the bag at any point and certainly wouldn't have allowed it to remain partially open.