Pennsylvania’s Bucks County Playhouse has seen two of its world premiere productions transfer to Broadway within the past four years: Terrence McNally’s Mothers and Sons, starring Tyne Daly, and Misery, a play by William Goldman, based on the Stephen King novel. Will the Playhouse’s current production of the new musical Cake Off be the next to move from bucolic Bucks County to the Great White Way? Probably not.