You didn’t mention WY in your list of states to visit. However if you are also going to YNP, GTNP you will probably travel thru WY. This post is information about Hwy’s 14, 14A and 16 over the Big Horn Mountains in North central WY.
We have traveled WY Hwy’s 14, 14A and 16 both directions East and West over the Big Horns. 14 & 14A solo without the RV, 16 with/without the RV quite a few times.
WY #14- 47 miles between Greybull and Burgess Junction including 18 miles of 5-7% grade with a elevation change of 4600 feet.
WY #14A- 52 miles between Lovell and Burgess Junction including 10 miles of 10% grade with a elevation change of 3600 feet.
The above information was obtained from a road information sign at Burgess Junction going West (down hill) Also both routes have a few 20/25 MPH hairpin curves thrown in just to increase the pucker factor. BTW the elevation of the town of Burgess Junction is 8041 feet.
WY #16 In our estimation is overall generally a better road. Which ever way you look at it all three routes cross the Big Horn Mountains. #16 is the farthest south where the Big Horns gradually meet the high plains.