I have traveled 3 time to Alaska in early May.If you earlyer you may meet some white stuff falling from the sky.
If you get tired there are a lot of road side rest stops that you can spend a night. They rather have you of the road in a road side rest than in the ditch.Buy for your self a book called Milepost it will give you all the data you need for the trip.
Two things I would recommend are.
1. Carry about 10 galons of fuel for your vehicle. So if the place is closed you stop in you can get to the next one.
2.Always fill up when you hit half full on your tank. Becouse the next place may be 150 miles down the road. Do not look at the price becouse it will scare you. As I tell the wife when she starts to complaine (if you can push I will look for cheaper place.)
The highway is good. It is two lane all the way and is back top. There few place that are under construction, but all you have to do is slow down.
The worst part is between Haines Junction and Beaver Creek. It has a lot chuck holes and a lot of frost heaves or dips in the road. Wach for flags by the road the mean a dip is there.
I hope to go again next year if health permits it. I have been going for Chemo treatments for Melenoma cancer. I schould be done in 3 months.
We will see.
Regards from Russell In cool and suny Tucson Arizona