When the going gets wierd, the wierd turn pro....
I don't know that there's any set distance to use as a guide, but it would generally be fairly close since people were traveling by horse and wagon then. Your best bet is to check and see if you can find plat maps for the area, also it's a long shot but look at the area on google earth and see if you can find any traces like evidence of road ways or foundation lines in the fields around it.
"That's me, on the beach side combing the sand, metal meter in my hand, sporting a pocket full of change"...... NOFX
Now in the process of posting my antique photo collection at : http://forgottonimages.tumblr.com/