I just went from Buffalo to Cody two days ago.
I took 90 to Laurel, MT; then south on US 212 to US 310, MT 72 to WY 120. There was about a 5 mile section of 310, just after I got off 90, that was a gravel surface and road under construction. A couple of flagmen stopping traffic. Probably didn't go faster than 10-15 mph. Pretty rough...thought I was going to loose a filling or two...bounced around pretty good.
After that, a relatively smooth pavement into Cody. It was an easy drive with rolling hill scenery along with a pretty good, 15 minute thunder storm.