During filming, the film crew would allow Kevin James's wife and two kids to go shopping around the Burlington Mall (film location in Massachusetts), while he would continue to finish filming his scenes.
Gary Valentine is featured as the singer at the karaoke bar, a reference to his Comedy Central Presents special where he gets the audience clapping on beat to start the show and approaches the microphone, only to punchline it with, "Man, I wish I could sing. This would be the perfect time!"
The trivia item below may give away important plot points.
The road where Blart chases Veck in the minivan towards "McGuire Airfield" (apparently corresponding to McGuire AFB in New Jersey), is actually the road toward Hanscom Airfield, adjacent to Hanscom AFB, in Massachusetts.