This Fourth of July, the flea market in Sumpter is condensed to Main Street, where you will find vendors throughout the weekend. In addition, catch a ride on the Sumpter Valley Railroad, www.sumptervalleyrailroad.com, Saturday and Sunday, with departure times at 11 a.m., 12:30 p.m., 2 p.m., and 3:30 p.m. The Sumpter Valley Dredge State Heritage Area…