By Lynn J. Richardson On July 15, local bluegrass banjo musician Daniel Grindstaff will do something he has always dreamed of — make his debut at the Grand Ole Opry. Three days later, on July 18, he will be back in Elizabethton, sharing his fabulous music with his hometown at the Covered Bridge Stage beginning at 7 p.m. He will be joined by his band, The Uptown Troubadours, which includes Kent Blanton, Derek Deakins and Kevin Richardson, as well…