The members of Trampled By Turtles have followed a long path from rock music to progressive bluegrass, but it’s been a path that has been rewarding for everyone involved, fans included. The group have steadily risen in popularity with a take on traditional American folk music that is intricate and evocative without deliberately reaching for the cheap seats. This is as authentic as Americana gets. They’ll be playing a loaded bill as part of Prospect Park’s Celebrate Brooklyn series. This is a free show, guys; take advantage.