Idaho Falls to Butte to Coeur d'Aline

Nice and scenic route, lots of things to see, lookout pass is IMHO nothing to worry about, do that route quite a few times each year, occasionally with a 35ft trailer. 6 percent or so grade on either side, but overall a good road. then is 4th of July pass, lower grade, and not as high.

We would be taking I15/90 route. Planning on stopping in Butte for the night then continue on.

If you want to get of I15 after crossing into Montana, take 278 toward Jackson. If you're real brave, take the 12 mile dirt road at Jackson back to the Miner Lake Campground (no hookups, but there is water available from a group pump). Continue to Wisdom, take 43 west to 93, then north toward Missoula and pick up I90 into Coeur d'Alene. OR, before Missoula, you can take 12 at Lolo down into Idaho, and then 3 north to St Maries and then pick up either I90 or 97 around the west end of the lake into Coeur d'Alene. It's a longer route, but beautiful. We towed our 18ft trailer last fall that way and loved it.

Well, I tend to use Interstates only when necessary. I like climbs, decents and two lane roads. It's the journey, Kear, not just getting to the destination. It's only about 600 miles.

Use this site to see the elevation and slope of everywhere on your route. Just pass your mouse over the graphs to see the numbers.

Elevation of about 4700 ft at Idaho Falls to an elevation of 6870 ft at the top of Monida Pass on the ID/MT border. It is a long steady climb. Lookout Pass is another climb. Your route is on the spine of the Rockies so you will run into varying degrees of elevation changes but if you are using I15/I90 shouldn't be a problem

Only interesting climb/decent is at the ID boarder on I-90 over Lookout Pass... normal max of 6% on a Interstate.

Do you favor Interstates (15 and 90) or back roads?

google earth and maps can tell you a lot.