Go to the very top of this forum and click on the 'Clicky': Helpful ideas for Alaskan Travel. It is, indeed, very helpful. Keep up with the current ongoing posts on 'Roll Call Alaska 2015' for additional questions answered.
For maps and history along your trip, definitely use the 'Milepost'.
For campground information, purchase online Mike & Terry Church's book 'Alaskan Camping'. It includes Canada and the Yukon, also. They lived in Alaska and traveled the route often. It's a much better reference for campgrounds and boondocking spots than the Milepost. Keep in mind that with both publications, things change constantly with closures which you will probably encounter. It's a trip that you'll just have to go with the flow.
I wouldn't recommend you arm yourself with guide books other than the two I just mentioned. They have all the information you might want.
There will also be closures on fuel stations so always drive on the top half of your tank and fill up when you see a spot. This is not a trip that you will be able to search for cheap fuel. Buy it when you see it.
Another thing to purchase online is the 'TourSaver 2/1 Coupon' book. Doing one glacier tour (a must) will pay for the book.
Don't strap yourself with making reservations. It will be a more enjoyable trip. The only reservations we made were for the July 4 weekend (Alaskans like to camp, too) and for the Denali Nat'l Park stay at Teklanika campground - the farthest one you can drive and well worth it. For those we only made them a few weeks out when we could judge our time better. We easily found our overnight spots otherwise without reservations. Plus, there are many gorgeous spots just to pull off the side of the road for a night.
Have a great trip!
Full-Timed for 16 Years
.... Back in S&B Again
Traveled 8 yr in a 40' 2004 Newmar Dutch Star Motorhome
& 8 yr in a 33' Travel Supreme 5th Wheel