My John Allen was born in South Carolina according to Census records. He had a son named John S. Allen. I think John S. was born about 1862 (off the top of my head) and I am pretty sure that they stayed in the White County Georgia area. There were a couple of John Allens in the area and unfortunately there seems to have been alot of James and John Allens in Georgia. Have you tried the libraries in the area your ancestor may have lived, there may have been someone else that has researched the family and left info behind? It could open a few doors or windows for you. I tried that with my Allen line and it has helped, although some of what I received was repetitive, I did find a few new things that were really exciting.