Galena Pass is 6% - not a biggie. Then you'll get on 93 to Missoula and you'll have Lost Trail Pass which is 4-5% and easy.
It's a beautiful drive. Plan to stop around Stanley and the Sawtooths - gorgeous! If you fly fish, this is the place to go.
Full-timed for 16 Years
. . . Back in S&B Again
Traveled in a 2004 Newmar Dutch Star 40' Diesel