Tips please for Detroit - Miami 10 day trip?

[Irish Roadtripper]

Myself and by buddy are heading on a road trip this Saturday (25th Oct) starting in Detroit and finishing in Miami 10 days later. We are 2 guys aged 27 and 25 and this will be our first USA road trip. We are hiring a car with unlimited miles and wondering what are the "must see" and "must do" things along the way. This site has been of great help so far and our planned route so far is like this:

Detroit - Toledo - Dayton - Cincinnati - Pigeon Forge - Smokey mountains - ?

Not sure where to go from here so any suggestions are welcome. The more scenic the route, the better. We're also open to any alterations to the above route. I'd also appreciate any accommodation ideas (motels etc)
We are both petrolheads so we plan on seeing the Floyd Garret Muscle Car Museum in Pigeon Forge and hopefully catch a Nascar race in Miami later in November.

Thanks in advance...