Your trip will grow.
Here is one branch to consider adding.
US 93 goes through Idaho and western Montana, and it is very pretty. I rode it south to north, but it would be just as much fun the other way (I looked in my mirrors, so I know this is so).
In Idaho, 93 follows the Salmon River, which Lewis and Clark pronounced as too turbulent to be useful for navigation in either direction. I agree, and that turbulence makes it fun to watch as you ride.
So I say take a look at US 93. Up in Montana it shows you the Bitterroot Range, and those are much lovelier mountains than we have in Florida or you have in Michigan.
I won't ride with you, because I am going other places, but you will cross my tracks a lot, and if you have as much fun as I had making those tracks, you will enjoy your ride a lot. And how could you not?
Good luck, and as we atheists say, dogs peed.