For new Alaskan travelers it would be your worthwhile to go to the very top of this forum. You'll see a "Sticky" for Helpful Hints. It has lots of good information to prepare for your trip.
As to the direct question: install new tires on your vehicle if they're about due. You're correct in taking extra fluids, belts, air compressor. Other than that, just travel the way you would on secondary roads in the lower 48. It's no different. It's an easy trip nowdays. Drive slow and you won't get any damage. You'll find out what frost heaves look like from a distance after you go over the first one! :) They're easy to spot.
There are plenty of gorgeous spots to spend a night just off the highway. Many folks do so. There are RV parks around every town but they won't look like the kind in the lower 48. For the most part they are just gravel parking lots. We much preferred the roadside stops and the public parks, especially in Canada and the Yukon.
The roads aren't deserted and you'll have many folks traveling the same route as you. In fact, you'll probably see the same faces over and over again.
The only reservations we made were the July 4 weekend (Alaskans like to camp, too) and our stay inside Denali Nat'l Park. For those we made them as we were traveling and could better judge when we'd be at a certain place.
Just take your time and enjoy the trip. It's fantastic!
