Mission markers are the surnames of Grammy award winning or nominated female country singers: Lambert - Miranda Lambert Musgraves - Kacey Musgraves Morris - Marne Morris Parton - Dolly Parton McEntire - Reba McEntire (Last three markers illegible)
Early in the episode Jason indicates he passed Musgraves and Underwood. Presumably he referenced Carrie Underwood as one of the mission markers. The board also shows Carter (presumably June Carter).
Clay has a Bible verse tattooed on the right side of his rib cage: Genesis 27:3 which reads "So at this time take, please, your weapons, your quiver and your bow, and go out to the field and hunt some wild game for me".