Hi Matt, if you start out with new tires front & back you should not need to change a tire from your home to Alaska and back.
I have rode a motorcycle to Alaska & back 3 times from our home in Michigan. On a /63 R60/2 with a R60/6 motor , a '91 R100GS/PD , & a '95 R1100GS . Starting with new, duel sport...mostly road type tires The fist two times . They were wore pretty good by the time I got home , but they were still usable for a few more thousand miles. The third time I had new TKC80's kobbies on my R1100GS. We were going to Inuvik NWT then over the top of the world highway then up to Eagle Alaska. I new the Dempster , top on the world , & the
Taylor highway could be a challenging if the weather went bad, so that is why I went with the knobbies . I did take a new rear TKC80 with me & put in on around 3/4 way thru the trip. But , I put it on partly because the rear was getting wore out & partly because I was getting tired of tying the spair on my bike ever day.
Two of the other bikes on the trip used D/S tires with no tire problems . One other had shipped Knobbies on ahead to Dawson & we put them on there. As I remember he left the tires he road up there on there & run the knobbies the rest of the trip.
I have been to the BMW dealer in Anchorage twice , they were nice & help me out. Once my fuel valve started leaking , & they put in a new one & once I needed to put in a new battery.