Dean introduces the brothers as US Marshals, using the names Billy Gibbons and Frank Beard. They are members of the band ZZ Top.
The "Lost Colony" that Sam mentions is actually a real colony. The Roanoke Colony, also known as the Lost Colony, established on Roanoke Island, North Carolina, United States, was a late 16th-century attempt by Queen Elizabeth I to establish a permanent English settlement. The final group of colonists disappeared during the Anglo-Spanish War, three years after the last shipment of supplies from England. Their disappearance gave rise to the nickname "The Lost Colony". To this day there has been no conclusive evidence as to what happened to the colonists, although the prevailing theory is that they assimilated into the local native population.
Dr. Lee tells the brothers that the next town over is Sidewinder. A reference to the town of the same name used in The Shining (1980) where the Overlook hotel is located.
Dean says, "That was kinda creepy, right? A little too Stepford." He is referring to the thriller The Stepford Wives (1975) wherein husbands in the town of Stepford kill their wives and replace them with robots who fulfill their husbands' every wish.
Dean tells Sam, "Man, I don't know. I feel like Chuck Heston in The Omega Man". The Omega Man (1971) is a sci-if thriller featuring Charlton Heston as the last non-mutant man on Earth after biological warfare devastates the world's population.