Thanks for your response! I'm glad to know there are other researchers out there interested in these lines, too.
There was a Hester Bedwell (also written in some records as Esther Bidwell) who married a James Gammill, but she married *James Gammill, Jr.*, son of James Gammill, Sr. and Margaret Miller, not James H. Gambill, who is in your line. This James Gammill, Jr.'s line is well documented, as is where he went after Bedford County, Tennesse and his descendants.
I've not been able to find out who James H. Gambill married, which is why he's still in the running for me, unless I can establish that he married someone other than Sarah --- (possibly Whites).
James Gammill, Jr. was the brother of William Gammill, Sr. who married Anne McGaughey. William Gammill, Sr.'s son James Gammill who got $1 in his father's will, is the most likely candidate, because this James' brother, Andrew, married a Jane Whitis, possibly a sister to Sally Whites. If some descendant of *this* James Gammill knows who James married and where he went, that would eliminate him as a likely person to be my 4xggfather.
This is why Y-DNA testing would answer definitively--since I've been researching this topic for some time--which line our James belongs in. The above 2 Jameses were in the right small place, time, general time frame, and are otherwise unaccounted for.