Did the Dalton two summers ago on new Heidenau K60 Scouts. From Az. to the arctic crcle and back was 8K miles. I hit the Dalton at about 3800 miles on the K60's and there was plenty of tread for that road to get me up from Fairbanks to Prudhoe bay and back.The problem isn't a nail up in Alaska it's a sharp rock cutting the tire and only a new tire or tube will keep you going.. It's 200-250 miles between fuel stops on the Dalton Highway (1000 miles of dirt round trip)
That being said most don't have a problem even with street tires. I plan on running Dunlop Trailsmart tires up and putting new Dunlop Mission tires on in Fairbanks before heading north as mine should be about shot just getting there. My buddy is going to try to do the entire trip with one set of Motoz trackionator GPS tires on his GSA. Those tires have a very good reputation doing just that. He is going to carry a tube but I'm just carting a repair kit.
One of the guys I rode with had street tires and less than 35% left on his tires, and he made it without issues also. He needed a new rear somewhere back in Montana so his rear has perhaps 2K left on it when on the Dalton.