If the actress playing Mary Beth sounds awfully like Dolly Parton, that's because she's played by her sister, Stella Parton.
Luke remarks to Bo that the ambulance has an engine problem "that's religious in nature" because Bo "had better pray that Luke can fix it". Then when the gang rolls into Possum Hollow to gas up, a large white church is prominently shown in the background that about fills the entire height of the frame.