I was fortunate enough to be able to take a trip roughly along those lines with my dear mom (well, more focused on Alaska and less so on the western continental US national parks), and posted a
travelogue (with pictures) here afterwards. It might give you some ideas to consider.
I think the places that most stand out to me from Alaska, the ones I'd most like to see again and spend more time at, are Kennicott / McCarthy and the Dalton Highway, at least as far as Galbraith Lake. The Dalton highway was most definitely hard on my motorhome, though; it's hundreds of miles of variably rough gravel road, and gives everything a thorough shaking and (on the days I was there--conditions are very much weather-dependent) a very complete mud bath. The scenery was well worth it to me. There were a good many other only slightly lesser highlights.
The Beringia Interpretive Center museum in Whitehorse, YT is absolutely fascinating, as well, and definitely worth seeing if you're going through the area--and you will be if you're driving to Alaska.
Get the milepost; it's handy even though it's largely advertising. Get Church's book on Alaska camping. Get the Benchmark atlas of Alaska. Get comfortable with dry camping, if you aren't already.
