We did a somewhat similar trip in 2014. We left Virginia in mid May and returned in late September. We travelled across and made stops in the Badlands NP, Devils Tower, Yellowstone NP, Glacier NP and crossed over into Canada on the western side of Glacier and up to Yoho, Banff, & Jasper National Parks and then up the Alaskan highway to Alaska. In Alaska we visited Skagway, Haines via ferry, Valdez, Anchorage, Seward & Homer on the Kenai. From there up to Denali, Fairbanks, town of North Pole, and back south. We took the Cassiar highway down British Columbia with stops in Stewart and Hyder.
A great RV adventure. We knew our general route and played it by ear by adjusting our campgrounds and stays as desired. The only reservation made for the entire trip was in Denali NP. It truly is RV friendly in that there are numerous places to Boondock, provincial parks, BLM, State, and national parks. I suggest getting the Milepost book for the Alaskan highway and Alaska Camping by Church
https://www.amazon.com/Travelers-Guide-Alaskan-Camping-Alaska/dp/0982310110I would like to do it again but not sure that will happen. Wish you a safe and enjoyable trip.