People seem to do it and end up just fine up north. I saw one or two around Dawson and between there and here during my vacation.
I guess around here people use different methods other than just thumbing too. I see a lot on Alaskalist and Craigslist, community message boards with rideshare space usually have requests, couchsurfers email locals or post in forums on that sight asking for people heading to different destinations.
Yet I still see thumbing a lot too.
I don't usually pick anyone up, since when I'm going anywhere of any decent distance I'm usually traveling heavy in the truck and really don't have any space available short of the truck bed which will earn the driver a ticket and be an awfully rough ride down these highways.
Up here it seems pretty safe, since I see so many people doing it. Just be prepared to walk, as the general consensus (funny I just had this convo with friends a week ago or so) is that if the person is making the effort and walking in the direction they want to go, people are a lot more apt to pick you up.
Personally, I'm a lot less apt to unless I happen to have a shiny metallic friend hidden in the car. Girl can't be too safe anyway. Plus for a long ride especially up here I don't want to end up picking up a person that will make me insane. Or someone who has some sort of ramped mutant BO that stinks up my car.
So overall do-able, but you might have to do some work around figuring it out. Don't forget if you want to visit Alaska you need a passport to get up through Canada. Beautiful area to ride up through too. I highly recommend it!
