John, I tried to send you a response the other day, but don't see it on the list. Try the following: www.carolinaforestry.com/vincent_allen/vincent_allen.htm
You can also search google for "Vincent Allen House".
The web site lists Vincent Allen's 1790 house for sale in Vance County NC.Vance county was formed from Granville and Warren counties in the early 1800s.The web site has directions on how to get to the plantation, maps of the area, arial photos and photos of all the buildings and fields.It also mentions a cemetery in the side yard.
Since I wrote you, I received a reply from the agent, and he tells me that no Allens are in the cemetery.They are all grandchildren of Vincents or later through his daughter Agnes.However, he does state that Charles tombstone is across the road.
Vincent Allen and his wife, Mary Bowdoin, are my 4greatgrandparents.I am very interested in any information you have on the Allens.If you happen to get a photo of Charles' tombstone, would you send me a copy.I will be happy to cover associated costs.