Two to three months - hurray!
Banff and Jasper on the way up, definitely good, and then Kluane.
A sidetrip from Haines Jct. to Haines - you'd get Chilkat Pass and Haines (gorgeous, plus a taste of Southeast)
Dawson and the Top of the World HWY - we made that trip in the early fall
and really liked it
Richardson Hwy to Valdez has some topnotch scenery (Wrangall-St. Elias Mtns), glaciers, etc. A side trip off the Richardson towards Chitina has the nice but tiny Liberty Falls CG. And we've been beyond Chitina over to McCarthy, which is a long 60?mile road (old RR grade) , but McCarthy and the old Kennicott mine area is pretty cool.
Denali HWY - mostly gravel, but gets up high with good views of mtns. (Paxon Lakes area BLM campground has lots of skeeters) Used to be the only way to Denali before the Parks Hwy was built.
From Fairbanks to Chena Hot Springs - neat sidetrip, but road close to Fairbanks is "interesting"due to melting permafrost.
Denali - high and magnificent, but sometimes hard to get camping spot in the park and most have to do bus ride to go into Wonder Lake. But it's worth stopping and at least driving in the first allowable miles.
Anchorage and surroundings - beautiful country, too bad there are so many people.
Hatcher Pass is cool, too, but road up there is interesting.
AND THE KENAI PENINSULA (where I live) - beautiful place with a little bit of everything. The drive down to Seward is splendid. (Ptarmigan CG is our favorite, small and quiet) The road over to the east side (Soldotna, Kenai, Homer) takes you out of the mountains with lots of lakes and moose, and then you get down to Homer and Wow! - there are the mtns. again, with Kachemak Bay and glaciers spread out before you. Good fishing on the peninsula, too. We live near the end of the road north of Kenai, and there's a very nice campground at Capt. Cook State Park. About the only thing I don't like about the peninsula is that on the weekends there is often heavy traffic from Anchorage, and they fill up our campgrounds.
Bring warm coats - you'll need them.
Hope you have a splendid, awesome trip.