You rarely catch Barney and Gomer out of their uniforms - deputy and service station attendant, respectively. When you do, they're more than likely going on one of Mayberry's famous picnics. Even then, this pair is quite a team.
Take the time that Andy and Helen get trapped in a cave-in while on a picnic ("Barney and the Cave Rescue," Episode #109). Under Barney's calm leadership, Gomer is a big help in rescuing the lost lovers.