When the helicopter lands beside Old '97 there is a location printed below "Copters Unlimited." Hillgrove, RI was too revealing that they weren't in Maine, so they covered it up for the takeoff without fixing the landing shot.
When Old 97 leaves Cape Ann for the lobster run, a close-up of the locomotive's wheels shows them turning backwards. It then cuts to a longer shot to show the train moving forward.
When Mr Malone is talking with his colleague about the poster and adding more "broads", he has a piece of lobster in his left hand. When the camera goes back to him a split second later, the piece of lobster is missing. His hand never left the screen to put it down.
Near the end, when the helicopter lands at the track where the engine has run out of steam, it says "Copters Unlimited" on the tank, with the name of a town in Rhode Island. In subsequent shots, the town has been covered with white tape.
Around 01:10:48, when it's travelling to the left, equipment shadows can be seen on the car.
While the story supposedly takes place in Maine, in a railroad scene the Connecticut State Capitol can be seen in the background.
The movie is supposed to take place in the Bangor, Maine area, but the microphone that Gene Rayburn is holding and the supporting television truck is for WTIC, a station in Hartford, Connecticut--a good 300 miles away.
At around 6 mins, George raises his right hand and says "Cub Scout's Honor" to Jane, but he is showing the *Boy* Scout sign (3 fingers) instead of the *Cub* Scout sign (2 fingers). As a Cub Scout leader, he would be well-acquainted with the Cub Scout sign.