value of home with no comps in area?

Trying to determine the market value of a old home in nc (1920) but there are no comps. in the local area of this sq. ft. or age.

I would try to find properties in the same municipality–anything built from 1900 to about 1930 or 1940. Adjust up or down based on square footage differential or age. In my area ¶, I use $35/SF and $1K/year of age.

Nancy