I have a tree on Ancestry.com that I believe shows your lineage back to Robert Lancaster Sr (ca. 1631-1720), founder of the Surry County, VA, Lancaster line. It's a private tree that I can invite you to view if you send me either an email address or your Ancestry username. My email is firstname.lastname@example.org.
According to my information, William Lancaster (b. 1732) is our most recent common ancestor. I descend from his son William Sanders Lancaster (1760-1813), and you descend from his son Wright Lancaster.