When you hit a brick wall and the ancestor whose parents you’re looking for owned property, try and find out who owned the property previously. The previous owner may have been related, if the ancestor inherited the property, or may have created a sale or conveyance record that mentions your ancestor.
For an example of how useful tracing the previous owner can be, read my article “Griete Smith’s Parentage: Proof in the Absence of Vital Records” (PDF) as it appeared in the December 2016 issue of the National Genealogical Society Quarterly.