Does anyone have information on John Kennedy b 1768 Somerset Co PA ---d. 1832 Sydney, Australia m. Mary Catherine Runner b. abt 1770 in MD --- d. 1870 Monongalia WV?

My 3rd Greatgrandfather John T Kennedy (b. 1812 Saltlick, Fayette Co PA or Donegal, Westmoreland Co, PA --- d 1896 West Elizabeth PA) lists his father as being born Ireland and mother in MD on the 1880 census and I have traced this family on the Saltlick and Donegal twp census rolls from 1810-1840 (only Catherine appears on the 1840 roll). I have correlated this research with a document of John T Kennedy from 1835 that lists his neighbors. It's a little complex, as are all these genealogies prior to 1850.

I think that this family maybe the family of John Kennedy and Mary Catherine Runner but I am reluctant to accept this conclusion without any supporting evidence. It seems preposterous that this John Kennedy would battle Native Americans and land grabbers on the western PA frontier and pick up to go to Australia in his golden years leaving his wife and children...but I guess anything is possible. I am very very curious of this story.

I appreciate any and all help!

Thanks!