I'd recommend that you start monitoring the 2016 Alaska post of travelers which has been going on for about a year.
Purchase online three things before you go: the Milepost which is excellent for maps and history; Mike and Terri Church's Alaskan Camping which is all you need to find RV parks, public parks and great boondocking spots. Finally, purchase the TourSaver 2/1 coupon book. One glacier day trip will pay for the book and you'll want to do at least one.
Keep in mind that since you stated your destination of Denali, that is not the only place you should be striving to see. There's a lot more. :) Stay in Denali itself for the best experience. We spent 5 nights in Riley Creek campground and 5 nights in the farthest one you can drive - Teklanika campground. Our days were full and we saw 'the mountain' 7 of 10 days.
It's not necessary to make a lot of reservations for your trip. The only ones we made were for the July 4 weekend and for Denali's Teklanika campground. Those were only made about 3 weeks prior when we could better judge where we'd be. We even got into Denali's Riley Creek campground with our 40' motorhome as a unplanned thing. We were a little too early for our Teklanika reservations so on a whim we boondocked outside the park at a lovely spot the prior night and drove into Denali early the next morning when folks were leaving and we easily secured a site for 5 nights.
Keep in mind that fuel in Canada will cost a lot more so stay in the U.S. as long as you can before crossing the border. From Arizona we headed up to Washington and crossed at Sumas which was easy. We crossed the 3rd week of May and returned to Montana near Glacier Nat'l Park the first part of September.