My 3rd Great Grandmother was named Lydia Longshore, b. abt.1815, died 12 July, 1844 in Morgan County Indiana. She married William Best of Zanesville, Muskingum County, Ohio on 15 September, 1836 in Muskingum County, Ohio. Her parents were an Amos and Nancy Longshore. Could this Amos have been a brother of your David Longshore? Would be interested if you have found anything on an Amos Longshore in Muskingum County.