JOHN LONGWELL Caroline Co,Va. to Texas

John Longwell and his wife, Marthaleft Caroline Co. Virgina on a Wagon Train heading to Burleson county,Texas in 1857. They had three children : Lucy born 1854 in Va, Callie 1857 and Harry 1859..these two born in Texas.What happened to these children? Also would like to locate John Longwell's parents.John died in Texas in 1868 but I do not know when he was born.Martha born 1824 VA and died 1906 Caldwell,Texas.Any help appreciated.