We would rotate who got to be at the front on long treks (Philmont). As the 'head' of the snake, you take ~100 paces or whatever, then you step off to the side of the trail until the entire group has passed you. You are now the 'tail' of the snake. The new head of the snake then steps off after 100 paces and everyone passes them etc. The side benefit is that everyone gets to take short rests as they wait for the 'body' of the snake to pass them.