In the hospital, Sam and Dean identify themselves as Mcvie and Fleetwood of Fleetwood Mac. When Mick Davies comes in as the doctor, he calls himself Doctor Buckingham, also a name from Fleetwood Mac.
When Dean and Mick interrogate Connor, Dean comments on his fondness for high school girls by asking, "You get older, they stay the same age. Is that it?" This is a reference to Matthew McConaughey's character, Wooderson, in the high school comedy, Dazed and Confused (1993) who says the exact same thing for why he likes high school girls.
When making up an excuse for what he was doing the previous evening Mick says he "watched an episode of the Great British Bake Off." This is the original British name for the Great British Baking Show and far more likely to be used by an Englishman like Mick
Beatrice Quimby, Claire's alias, is a character from the Beverly Cleary books, the Henry Huggins, and Ramona Quimby series.
The woman who plays the mom in this episode played a dead sheriff's wife in S6 E13, Unforgiven.