When Gavin is making small talk with Robert and Earline he asks why their grandson moved to Waco, Texas. She replies that he sings and plays guitar at a church in Mount Carmel. David Koresh did just that as the leader of the Branch Davidians.
Gene Jones, who portrays Robert, enters the diner around the 27th minute mark. He is credited as the Gas Station Proprietor in the Coen Brothers' film "No Country for Old Men." In the latter, he plays opposite Anton Chigurh, portrayed by Javier Bardem, in the famous coin flip scene.