Best Class C Route from Great Falls, MT to Bend, OR

[LyndaG]

Hi
What is the best class c route from Great Falls, MT to Bend, Oregon? Thinking of going south on I15 to i 86 to I84 then head south at Ontario on Hwy 20 E
Looking for light grades and smooth roads.
Suggestions?

[TravatoJohn]

Been on those roads many times in my former rig which was a 2003 Lazy Daze. Very easy drive. Very scenic in a lot of the areas. I’ve also towed on those routes with no issues. Enjoy. Travato John

[Fanrgs]

Are you planning any stops along the way? Are you interested in national monuments, history, boondocking, geology? Or just getting to Bend as quickly as possible? Depending on how long you plan to take between the two cities, there are some terrific sights--the Montana Capitol and museums in Helena, Virgina City, Yellowstone and Grand Teton NPs, Craters of the Moon NM, Oregon Trail Interpretive Center in Baker, John Day Fossil Beds NM, etc. We took US 20 from Bend to Ontario last year and should have taken US 26, which is much more scenic. But we were running short on time to get back home.