Some things have to be “done” in the county seat where the person lives. Other things do not. Would it have been easier for your ancestor to get married not in “their county” seat, but in the county seat of the neighboring county? Would the county seat newspaper in the neighboring county also have published an obituary for your relative? Is it possible your relative was sued by someone in a court in an adjacent county?
Never neglect the county seats in nearby counties, particularly if your ancestor lived near the county line.