“Oh no, we never gave that a thought,” says the Hackberry Ramblers’ Luderin Darbone about whether 70 years later the Lake Charles based Cajun-centric ensemble would still be whoop-hollarin’ and delighting crowds wherever their travels lead them. According to the nonagenarian fiddler, USA Today hails the Hackberry Ramblers as “the oldest band in the nation.” “We’re too old to retire,” Darbone adds with a chuckle.

Nor did Darbone ever realize that the last five years of the band’s m...