Old Waxhaw Presbyterian Church is located in Lancaster Co, SC. The boundary lines were not "set in stone" back then, so it was common for upper SC land to be recorded in NC and vice versa. That's why there is such a dispute over whether Pres. Andrew Jackson was born in NC or SC, because he was born in the "gray" area where the boundaries were not clear.
Here's some info on the church and early land deeds:http://www.sc.edu/library/socar/uscs/1997/waxhaw97.html
I've been there, but it's been years so I can't remember the names of the roads, but here's directions from someone else: "We left Lancaster on U.S. 521, headed north and took a left at West North Corner Road (between the Amoco station and a car lot; if you get to Andrew Jackson State Park, you've gone too far). At the dead end, we took a left onto Old Hickory Road. Not far down on the left we saw the church and cemetery."
I have a book about Providence Presbyterian Church in Mecklenburg Co, NC and it does list the first burial as John McKee d. May 17, 1764. His wife Peggy d.Sept 15, 1795.
Louis Pettus' book is entitled The Waxhaws, and it was privately published in 1993. I don't know if there are copies still available. I could not locate any used ones online just now. This is the last email address that I have for her: firstname.lastname@example.org
If that email address does not work, then you may want to post a message on the Lancaster Co, SC board. I'm sure someone there knows how to get in touch with her as she's a very well known historian of the area.