Seattle to Louisville, via Billings & Sioux City, touristy stuff recs wanted

Wall Drug

That’s still there? I have pictures of me & my sibs posing on “Dinosaur Hill.” So it’s definitely retro–but there’s some fine scenery where the plains meet the Black Hills…

But, in KC MO, which one?

After KC MO, driving 4 hours across MO on I-70, in STL MO you have to stop for some barbecue.
Pappy’s Smokehouse, top rated in STL, on Olive near SLU.

Map link: Google Maps