Teresa, I had suspected that your John was related if not the g gs of Capt. Richard Walker & Anne Shircliffe; Capt Richard (the 2nd, named for and heir of Capt Richard his Uncle), son of Thomas Walker 1st of Northumberland Co., VA & Elizabeth (?).
I believe that John would be the age to be a son of James Walker b 1744and Susanna Mattingly b 1749; they would have died in Nelson Co., KY; and suspect that James youngest brother William may have died in Logan or Kenton Co., KY.
James b 1744 was son of Joseph Walker 1718-1751 & Monica Stratford 1730-1754; son of Thomas Walker & Henrietta Kirkley; son of Capt. Richard. James siblings were proven to be Henry (Harry) Bennet Walker and Mary & Jane Walker
Most of the early records were destroyed in Northumberland Co, although there is much alternate and family info around.The names of your Thomas and Mary Sarah Coleman whom I have listed in my files but not connected named their oldest Thomas Randolph Walker (died in Texas), so names didn't help me.You say that Thomas and Sarah moving to Maury Co., TN about 1811.Do you have documentation that they were in Northumberland Co., Va area until 1811?If Thomas was James' son he would have been moving West much earlier.
Thomas 1st had a son named William, who named two sons by different wives, William.This could also have been the family of your Thomas.Familes they migrated to TN might be a lead, as I know some of the in'laws of that group.
Do you have a Walker male descendent of Thomas that could participate in the Walker DNA Study?We are Group 9. W. Ray Walker