this is so cool. i love this lost town & road stuff. interesting.

 

q: i take the last is a pic of where the real "national road" deviates from rt40 a  bit?

You are correct that this is such a location (road rerouted due to conservancy district retention basin, which are those bottomland pix near the top), but that pix is I think an old railroad grade that has been converted to a bike path.  Believe it or not these pix are not that far from "downtown" Vandalia

That is some cool stuff!