The Quad-City Times has an article on David Darby, who has led the effort to get old US 6 signed through parts of Iowa. It may be a little much to say he “found the old route through all these towns in Iowa,” since a 1979 map would show the pre-I-80 route except for between Atlantic and Adair. However, that would depend on how “original” he wants to get. (As I think I said earlier, “Historic US 32” would have been neat as well, but calling it old 6 ties it more into the cross-country road.)
Thanks to the U of I Library’s online publication of Huebinger guides, the 1912 River-to-River Route can be traced today, and I did part of that this summer. The River-to-River became US 6 east of Des Moines.