I found this information on the Latter Days Saints website.LDS inserts another generation between William C. and John Sims, and has the connection to Scotland.
William C. Sims was born May 4, 1826 in Georgia.He moved to Lamar County, Alabama, at some point married Sarah B. "Sally" maiden name unknown who was born in Pickens District, Pickens County, SC on October 23 1829.The child my husband descended from was John Allen Sims, born 1865 in Lamar County.
William C. Sims mother was unlisted.His father was William Sims born in 1809 in Pickens District, Pickens Co. South Carolina.He died in Alabama on an unknown date.
William Sims' mother was Elizabeth Sim (maiden name) born in Elie, Fife, Scotland on May 28, 1779.Death information unknown.Her mother was Agnes Thomson, born about 1745 in Pittenweem, Fife, Scotland.Her father was William Sim, born in Elie, Fife, Scotland in 1742.
William Sims' father was John Sims, born December 28, 1785 in Elie, Fife, Scotland and died March 22 1853 in Glasgow Scotland.I guess life in the United States didn't work out.His father was Alexander Sims, born about 1759; his mother was Christian Fairholm born about 1763.
I would be interested in hearing from any relations.