Thanks for the encouragement, Lifey!
I do realize that we're trying to cover quite a bit of mileage - and no one has suggested that the Calgary to Seattle leg has much to offer... It looks like the (potential) price difference between returning the RV in Calgary vs: Seattle (mileage and extra few nights) is only slightly less than flights for the family. That would give us the extra days deserved for the major stops!
A few more questions from folks:
1) Where do you suggest we stop for the night between Denver & Tetons?
2) Where do you suggest we stop for the night between Livingston & Banff?
And would two days each in Tetons, Yellowstone & Banff do it justice?