I like I-80/Nebraska instead of I-70/Kansas as Nebraska is not as boring as Kansas. By cutting the corner on 2 from Nebraska City to Lincoln it's 50 miles shorter than going to Denver. The two best ways to see Kansas is at night or from 30,000 feet.:B
Instead of 89/26 after Jackson, I would and do go in the south entrance of Yellowstone to get to West Yellowstone with my 42' pulling a toad plus it's 60 miles shorter and a easy scenic drive... only a couple of places where traffic slows down. Like I said above... eat lunch at Old Faithful.
If you by byway of Denver you can bypass Cheyenne by using 289. 89/6/191 are good roads, but not very scenic. How many days do you have?