Re: Mary Frances Mckinnon
I suggest getting James and Mary's death certificates from the PA Dept of Health. They should have the parents' names. Did they have any siblings? What do their obituaries say?
They were married ca 1888. If they were married in Pennsylvania the record of their marriage would be at the Register of Wills office in whichever county they got the license. Naturally it would be good to start with McKean County. Pennsylvania marriage records, particularly the application, usually has data on the parents.
Check with the McKean County Historical Society, Bradford Area Public Library and the Bradford Landmark Society to see if they can help you.