Last Saturday night, indie-folk singer/songwriter Gregory Alan Isakov and his band came to Boston and were greeted by a sold-out crowd at Roadrunner. With no openers and an upcoming album still in progress, the evening was a distillation of Isakov’s current body of work. The audience was treated to a setlist that featured a balanced mix of songs from his three most recent studio albums and a small sampling of everything else, all vibrantly performed by Isakov and his band. With a minimalistic stage production, the emphasis was on Isakov and friends. The concert ended with two separate encores that saw each band member crowded around a single microphone, and he stripped-down performances of “Dandelion Wine,” “Saint Valentine,” and “All Shades of Blue” made a room filled with thousands feel intimate. Fortunately for those who missed out on last weekend’s concert, Isakov noted that it won’t be long before he returns with a new album.