Robert J Sanders and Lula Blackwell

I'm moving this to it's own discussion on GeneJ's suggestion. Thanks for the help!

I'm looking for my great grandparents Robert J. Sanders and his wife Lula Blackwell. I've found them on the 1880 census in Clay, Lafayette, Missouri, but nowhere else. Robert was born about 1855 in Kentucky and Lula was born about 1855 in Virginia. Their son, John Lewis Sanders b. 1877, was my mother's father.

Gene, I did find that same census. Lewis is Robert's father. Looking into the deeds would be the way to go. Would they be listed anywhere if they were renters? Thanks for all your help!