Any easy day on the road. And state #37 for me (not on this trip... in my lifetime!). We deliberately chose this route to add a couple of new states to the map on the side of our trailer.
Walnut Grove did offer a more reasonably priced tour of their Laura Ingalls Wilder museum than did De Smet. Of course, none of the buildings were the actual ones that Laura lived in, but still... There was a replica of the dugout the Ingalls family in which the Ingalls family lived in On the Banks of Plum Creek. It's hard to imagine a family of five living in such cramped dark quarters for a year, or however long it was they lived there!