Does a document or record indicate how long someone has known your ancestor? Subtract back and see just when the two individuals met? Does it mean they knew each other "somewhere else?" Maybe that was back east, back in Europe, etc.
Testimony in court records, affidavits in pension files, passport applications, and other materials may include such statements. Always think about the time frame they suggest and see if there may be subtle clues you haven't fully used.
