..helped me locate my ancestors' farms. There are a couple of County Atlases from around that time, that show individual farms. Names of rural landholders are written right on the map. I asked for some photocopies of the relevant township, and found the places in fifteen minutes.
Also, they might find old deed or estate info, which will have the location of property by section number. Then you can use another document, the section records, which record each transfer of the property within that section, so you can find out who they bought from, and who they sold it to.