When Larrick presents himself as an officer at the train station he says that he is from "Petersburg County" when in fact Petersburg is an independent city.
When Elizabeth hangs up the payphone, it makes the telltale clicking sound, but there's no followup sound of one more more coins dropping into the cash box. Since Elizabeth didn't make a collect call, she would have had to pay for the phone call herself, and the sound of coins falling into the cash box is much louder than the sound of the receiver clicking when it is hung up.
While tracking Jared, Larrick studies a map of the Hampton Roads, Virginia area, on which the I664 Monitor-Merrimac Bridge-Tunnel connecting Suffolk and Newport News is depicted. The bridge-tunnel did not exist until 1992.
Chrysler LeBaron that Beeman bought for Nina is a revised 1986-1988 model; the story was set in 1982.
The International school bus Paige is shown riding on is a 1993 or 1994 model, as shown by the front end and grille of the bus. An International bus from the correct era would've had large horizontal grille bars and round headlights. This has the smaller grille slots and rectangular headlights.