What is the function of the "drummer," the traveling salesman in Part II of "The Bride Comes to Yellow Sky?"

This minor flat character is used for both humour and detachment. His interruption upon the scene also precognizes an upcoming crisis as a sort of Greek chorus, Western style. It's the drum roll which builds suspense before the actual act is played out.

This character also helps maintain the lighthearted tone of the story. As this personna, the reader also observes without being emotionally caught up in an eventual small town shoot-out; he is, as the drummer, just "passing through:"

Crane is a deadpan satirist and mimic, prone to using cliches, stereotypes, and familiarities of plot episodes to spin out his yarns.

This tongue-in-cheek humour, use of "prefabricated" personae and emotional distancing could be considered in part the Crane trademark. The reader is not to take him too seriously, at least in his lighter works, but there is nevertheless a message lurking closely behind.