My wife and I have made 44 trips over the Ak. Hyw. since 1963.
The road now is completely different and vastly improved from the first trip in 1963.
I always carry the spares for the truck and RV plus another unmounted tire for both. It has saved me money and time along the way. There is always a place to mount your tire if needed and saves hauling another rim.
Basic tools, a spare belt, fuel,air & oil filter plus oil for one change. A spare headlight bulb (Canada requires lights on 24/7).
I also carry 10 gals. of diesel but rarily use it. When you get into Alaska dump it in the tank and keep the jugs for your trip back.
There are many services along the way but they can be expensive. Watson Lake & Ft. Nelson are both notorious rip-off places. Whitehorse is a modern town with any services you may need and much more reasonable in price.
There are Dodge dealers in Dawson Creek, Ft. St. John, Whitehorse, Fairbanks, 2 in Anchorage and in Kenai.
I hope this helps. Just ask if you have any questions.
Jack in Alaska