Re: Virginia Tilghmans & Maryland Tilghmans
Are you certain that the William Tillman you're researching is the son of George Tillman of Virginia?
There's a curious document that names a William and Nancy Tillman that's stumped another Tillman line for years. In 1806, Stephen Holland Tillman (b. 1738 in Maryland, son of Gideon Tilghman)signed a document freeing his slaves. In that document he mentions a William and Nancy Tillman that researchers have been hard pressed to locate. Stephen Tilghman (Tilghman and Tillman are, of course, interchangeable) was in Eastern North Carolina by the 1760's, then York, South Carolina, then Mecklenburg County, North Carolina, and eventually Kentucky.
Many of Stephen's Tilghman/Tillman clan were in Georgia in the late 1800's. This included an Aaron Tillman who was probably a nephew (b. abt. 1774 in South Carolina) He lived in Jackson County. I also see a few allied family names pop up in the same area (Bryant, Harrison) so it leads me to wonder if the William you're researching isn't instead related to the MD/NC Gideon Tilghman and not the VA/NC Roger Tillman line.
Did the info on your William's line come from one of the Tilghman books? As I think you've pointed out, those books are riddled with errors and more than a few stories that I can only explain as being "made up". If your information came from there and you've hit a brick wall, you may want to look at the other Tilghman line.