ROUTE suggestions request: Palm Springs CA to Hamilton MT

[Bubblesyeah]

Hi

This is going to be my first trip (alone) travelling from Palm Springs CA to Darby/Hamilton MT with dog and cat, this summer 2016.
I am looking for some or a safe route(s)as my hubby is flying in later into Missoula MT due to work.
Any help is appreciated also maybe safe spots to overnight park. Planning to arrive within 2-4 days, since I am on my vacation right?
I would like a nice relax route since I would like to enjoy the scenery (don't wanna eat just miles on the freeways only)
Traveling in Class A 38ft rv diesel pusher. I am not afraid to drive the rv (as my hubby said years ago: drive the front and the back will follow LOL he went to take a nap after that).
I am planning to travel back by making a family visit in Brookings, Oregon.
THANK YOU so much in advance!!!

[twogypsies]

A couple routes: Scenic via US93/26 via Twin Falls, Idaho = 1077 miles

Interstate: I-15 to Idaho Falls and then 93 = 1114 miles

[beaverfever]

93 is a great highway but very desolate if. if this bothers you 1-15 is the way to go