Sounds like you're making good time!
So you can slow down and take more pics once you get there,,,, right?!?!?!
Yes, the wind will be with you for a long time now,,, as too will be the absence of shade!!!
You doing slab across SD? Guess it doesn't matter too much, about the only difference would be by HOW MUCH you exceed the speed limit!
Enjoy,,,, and ride safe!!!