I've heard tales of the Carters all my life. Known a few of them, Liptraps too. Mattie lived across the road from me growing up on Green Valley Farm.
My grandparents Bill and Libby Ingram knew them well.
You can contact William (Bill) Ingram in Millboro on Pig Run Road. Have to look him up in the 997 exchange if you want to call him. He can help you out with a place to start. He'd appreciate the company, I'm sure.
You can likely find some burial places at Green Valley Church Cemetery, and Rehobeth Church Cemetery in Millboro. I know Swearingins are buried at Rehobeth (on Pig Run Road). Some are collateral lines in my tree, but I haven't tracked them much. Grandaddy's late sister, Lillian, married a Swearingin.