Before Irena starts dancing with the cursed shoes, she places a small media player on top of the stereo. The stereo's display reads "no disc," indicating that it is in CD mode (not auxiliary or MP3 device mode), meaning it shouldn't be able to play anything from the media player. We don't see Irena switch it, so we shouldn't hear the music.
When Sam is driving very sleeping in the truck and, there are no trailer. When he has to avoid the big truck after he falls a sleep, there are no trailer, but when he pulls up in front of the dinner where Dean is at, there is a big trailer behind his truck.
After the scene where Sam and Dean disarm Timmy Sam incorrectly refers to an Edison Cylinder Phonograph as a Gramophone, while both are a type of phonograph, in that they are a device that 'reads' music via a needle vibrating over grooves, a gramophone is distinct as rather than using cylinders, as shown in this scene, a gramophone uses discs similar to that of a modern day vinyl record.
This episode is supposed to take place in Oregon, but Sam is holding an easily recognizable Tim Horton's (Canadian) coffee cup.