I'll throw out another idea for a trip to the northern Rockies.  Back around 20 years ago, when gas prices were
around $4.00 a gallon, my wife and I took the Amtrak from ND to Whitefish, Mt. to start out trip.  It saved a lot
of a long drive and was fun to experience a train.  We rented a car there, toured Glacier Park, and then on
to Canada and a night in Waterton, the Natl. Park lake is beautiful, and a great quiet little town.  Then up to Banff,
Lake Louise, and then across to BC and Kootenay Nat. Park, then on our way along and saw much of BC on
the west side of the Rockies. Stayed at a nice B&B, and finished our trip back to Whitefish, then train back to ND.  

Some years later we took our family with kids to Whitefish in the winter on Amtrak, and skied at Whitefish Mountain, a great
ski resort without the crowds of many of the others in the Rockies.  So consider using the train, eating in the dining car,
observation car, it is an experience.
The Empire Builder is the Amtrak route that runs from Chicago to Seattle.