The boat owned by Garth that Kevin is hiding out on is called Fizzles' Folly. Mr. Fizzles is the name of the sock puppet Garth used to talk to the little girl in Party On, Garth (2012).
After Sam and Dean kill a demon by way of Dean standing in front of him and waving hello to attract his attention and then Sam stabbing him from behind, Dean says: "well, not my most original work, but..." He is referring to when the Winchesters killed a demon in an identical fashion on What's Up, Tiger Mommy? (2012)
First time an angel blade is used to kill a demon. Usually angels just killed them by smiting. Although Meg does use one to kill a hellhound in season six Caged Heat.
Sam is staying in the same motel-room Amelia was staying in during an earlier episode.
When Sam and Castiel are watching Crowley's holdup, there is a car outside that bears a striking resemblance to Castiel's "Pimp mobile" in later seasons.