Hang ON Gramps, Here we go.
If you plan to cross into the USA in Detroit, look up the two local camp grounds and then plan two days at the Henry Ford Museum and Greenfield Village.
Headed south, get to both the US Air Force Museum, and Carillon Park and other stuff in Dayton. (If anybody in the group is a foodie, catch Jungle Jim's just north of Cincinnati.
When you get to Nashville, there is a "Pickers" store front that is fun and so is the rest of the mini mall it is in. Parking near it is a bear, but we have managed.
At the south west corner of the Nashville area is the head of the Natches Trace. This is a 444 mile long national park/road with no cross traffic and almost no services. Speed limit is 45(60) and it is scenery all the way. Before steam, settlers on the Ohio River would saw up planks and build a flatboat. Then they would make barrels and crates and then they will fill those with things that they knew that they could sell down the river. So, they would put them all in the flatboat and shove it off the bank. When they got to Natchez, they would sell the goods and then breakup the flatboat and sell the wood. Then they would take a couple of weeks to walk back north with their clothes, their rifle and their money. Now, that is a road with historical markers about every other mile (no Joke). Half way along is Vicksburg and that is a good stop on its own. It is our history, not yours, but interesting none the less.
I will keep looking at the eastern swing on the way north, but I don't have a lot that is close to that route.
Matt