“The Road Goes On Forever, and the Party Never Ends,” sang roots-rocker Robert Earl Keen. And for over two decades, it’s been an apt summation of the Greensky Bluegrass life, on and off the stage — until 2021, when the road ended, and the party caught an early Uber. For chief songwriter/mandolinist Paul Hoffman, who turned 40 last month, COVID cancellations forced the self-proclaimed “life of the party” to turn insular, facing a future no musician should have to contemplate: What if this is the end of concert-going as we know it? In their 22nd year, Greensky has been doing it longer and harder than most. In 2000, the band formed in Michigan as a three-piece with Hoffman, guitarist Dave Bruzza and banjo player Michael Arlen Bont, adding bassist Mike Devol and dobroist Anders Beck several ye...