I can scan a copy of the 1850 Census for Perry and Elizabeth, as well as Dr. Singleton's Death Certificate.
I am in the SAR, and been trying to find Robert Yearwood as a Militia or Continental Soldier for a few years. So far there is no evidence that I have found in land grants, Pension files, or NC Account Books. I believe he did move to Washington County, GA between 1784 and 1790, which was settled by many Revolution veterans. Washington County was formed in 1784 and land was given to many veterans for service, although Washington County records before 1825 do not exists because of courthouse fire.
You have probably seen my hypothesis proposing that Robert had two brothers, William and John, who appear in the 1790 Census of Lincoln County, NC, although I have no proof of this relationship beyond circumstantial evidence. Both William and John fought in the Revolution, William at the Battle of Ramseur's Mill Pond, and John at Guilford Courthouse and Eutaw Springs. One could guess that Robert probably fought in some of the same battles in NC, but that is speculation. I have also speculated that Robert fought at Augusta, GA with troops from Burke and Rowan Counties, NC, and that is how he ended up in Washington County, GA by 1791 where he appears as a Washington County tax defaulter in the Augusta Chronicle.