I made a tentative and shaky connection, I think, between Robert Sweadon and the sisters Sarah Sweeten Kirk http://www.wikitree.com/wiki/Sweeten-89 and Margaret Sweeten Kirk http://www.wikitree.com/wiki/Sweeten-88. I found a marriage between Robert Sweadon and Rebekah Covington http://www.wikitree.com/wiki/Covington-831 in a source (North Carolina Marriage Bonds) that I have never seen. It also bothers me that I need to find the siblings of these sisters.
Robert Sweadon may be the same person as a Robert Sweeten age 70-80 in the 1840 Census for Ripley Co., MO. Would Ripley County land patent and deed records be a good place to start looking?
There is more information about sources and my reasoning on the profile of Robert Sweeten.