Friend of mine lives south of Whitefish, MT and her mother lives on Whitefish Lake. I finally got to go up there last summer and really enjoyed Glacier NP, the rodeo at Columbia Falls (meat market after the rodeo), hiking Whitefish Mountain and doing some pseudo cryotherapy the next day in Whitefish Lake. Non-achievable for me thought since her dad bought the place in 1975 when he headed up to work on the TransAlaska Pipeline.
This is kind of a tough nut for me to crack because I've traveled a lot at different ages with my younger siblings and with my own children. At ages 3-5, they're really not going to get much out of it or remember much unless it's something really unique like the first time they've seen snow (which you've already done in Montana), or the first time they've seen some rare animal or something like that, or the fist time they've done a new activity like snowskiing.
Now that I think about it, with my kids, ages 3-5 were ripe for ski school. it's very expensive but, you could leave them in ski school all day where they'd learn something and have a good time playing. Meanwhile, you could be out skiing / snowboarding on your own.
The travel between places, learning to ride public transport like a train, or tram or streetcar in Europe was really fun. As well as seeing signs not in English and people conversing in other languages. Of course I always loved the money too. In the days before the Euro, the Dutch had the best looking money.
I will say that when my dad rented a Mercedes Station Wagon and we drove around West Germany in December, was cold and boring. But, it was neat to meet our long lost relatives in Ostfriesland.
We dragged my little brother and sister around Greece, Italy, Egypt, Australia, Singapore, etc. and like I said, wore out some Umbrella strollers. I'm not sure they got that much out of it.
With my kids, I started gradually increasing the flight duration - Denver to Houston, LA to Anchorage, LA to San Juan and finally when they were 9 and 12, we took the 14 hour nonstop from LA to Sydney when we moved to Australia.
I was 7 my first trip to Amsterdam and still remember the Legos on display in a toy store, the Tulips, and seeing the ships in dry dock at Rotterdam. I'd say that by age 6, those memories will start to become more permanent.
Sounds like you're trying to get them started off right, just don't get discouraged.
