For a man who had 15 children, you would think it would be relatively easy to find some traces of his descendants. I looked back into my research materials and the last note I have on Martha Farris Martin is a census count on 2 Jun 1900 in 4th Civil District of Coffee County Tennessee. I did not know that she left Coffee county after his death.
I have my gr-grandfather George W. Martin's bible and there is no mention of his mother, Martha Farris Martin in any of the family "records".
I made this comment in my notes, but it is purely speculative:
We know that the Farrar's were also in Nelson County Virginia and there are several marriages between this family and the Toms/Tomes. It could be construed by circumstantial evidence that Rufus Martin knew the Farrar family through their connection with the Tomes.