When Chuck "wakes up" late he walks into the kitchen carrying a box of Voodoo Donuts. This is a very popular donut store that has a few locations around the U.S. Chuck presumably is a fan because he would have to seek them out specifically as there are none anywhere near the boys bunker in Kansas.
Lucifer calls Sam, Metatron and Donatello "Larry, Curly, Moe." It is a reference to the American vaudeville and comedy act the Three Stooges.
When the boys meet the prophet professor at a police station in Oklahoma, it says on the wall, "Police State of Oklahoma 1914." Oklahoma became a state in 1907, not 1914.
Part of this episode takes place in Lewis, Oklahoma.