Mason’s Children, the California–based quintet devoted exclusively to the primal, free-wheeling era of Grateful Dead music from 1966 to 1972, will barrel up and down the Eastern seaboard this summer on a whirlwind seven-show trek they’ve dubbed the “Great Northeast Cannonball Run.” Known for channeling the Dead’s early psychedelic edge, the band leans into the quake-inducing jams of Viola Lee Blues, the shuffle of Big Railroad Blues, and the shimmering vocal blends