Other mistake: When Jack Nicholson is talking to the manager of the Overlook Hotel, the manager mentions the death of two girls aged 8 and 10. When Danny sees visions of the two girls they are unmistakably twins, not different ages. A quick look at the IMDb (http://uk.imdb.com/title/tt0081505/fullcredits) proves they are - Lisa and Louise Burns, both born in 1968.
Other mistake: When Ralph is leaving on his bike he passes the same rock twice.
Other mistake: After rescuing the boy, Jamie gets the 1946 Ford truck stuck, having rounded vent window frames. But inside as she tries to move the truck we see "dogleg" vent frames from say a 1963 Chevy truck (more pointed, angled back).
Other mistake: When John is talking about the murder of the child Claire yells at him to stop but refers to him as George. George C Scott is the actor's real name. (00:57:35)
Other mistake: David is trying to locate the beast through a map of the city - for some reason, since he already located it before. Problem is, the movie is set in Missouri but the map he's looking at on his bed is a map of Los Angeles (you can even read "Granada Hills"). Similar mistake a few minutes later in front of the sewers; you can easily read "Monterey Park" to the right of a different map he props against the wall. (00:37:15 - 00:38:35)