Here are some things that I have found while searching on the internet. I hope they help.
William Gamblin was born ca 1700 in Scotland and married Mary Given ca 1720 in Virginia.
William B Gamblin born July 24, 1727 in Bristol Parish, Prince George County, Virginia and died 1803 in Greenville, South Carolina.
William B Gamblin married Susannah Cole Wells in 1757 in Amelia County, Virginia. William was Susannah second husband. Her first husband was Thomas Wells. Susannah and Thomas had one child Lewis Wells born c 1750- died 1836. Susannah parents were John Cole and Abigail Rayburn.
I found this and I don't know if this is your Benjamin Lewis Gamblin marriage are not.
Benjamin L Gamblin married Rena Langford on October 16, 1898 in Hall County, Georgia.
The parents of Elizabeth Jane Barnwell was George and Ann(Warren)Barnwell.
Sion Gamblin was born July 24, 1777 in Bristol Parish, Prince George County, Virginia and died 1853 in Hall County, Georgia. Married Margaret "Peggy" Bramblett.
I found these two sons of William and Susannah also.
Joshua born c 1758 in Amelia County, Virginia. He had two wives. Annie Gray & Mary O'Bryant.
John F (didn't have birth or death dates) married Mary "Polly" Ray.
Faye aka Mrs Graybeard