Ha! Chateau, those locations may look close together, but a lot of driving on two lane roads is required. Plus, you add in all of the summer traffic (RVs, etc.) and one can become a very frustrated driver.
There's also a great change in elevation. Cody's only at 5000 feet. Yellowstone's roads are mostly at 7500 to 8500 feet.
If they visit Old Faithful, they'll have to make a loop in Yellowstome to get to Cody. You have to take a left at the T coming up from the Tetons.
Yellowstone is one of the greatest places I have ever visited but the driving sucked. Oh, I forgot to add all of the vehicles slowing down and stopping to view the elk, buffalo, moose, and other animals..
I don't expect an auto race in Yellowstone.