If you are a fruit toad like I am, I would stock up on FRESH fruit available in Prince George or Prince Rupert, as I am pretty sure Ksmloops, Terrace, or the rest of southern BC or southern Canada has real fresh stuff, but just enough estimated supply before crossing into Alaska or it will potentially be confiscated even if declared or you will be fined if not declared when asked.
As others noted, beyond Prince George or so the fruit is not so fresh as I do not recall buying fresh fruit in Grande Prairie or Dawson Creek.
In Fairbanks I only buy fruit at Fred Meyer where you have the best selection of fruit, mainly "fresh enough" but not overly great sometimes... as in comparison to the other chain supply stores that supply partially rotted or short shelf life stuff - the exact same condition as you will see throughout Whitehorse, Watson Lake, Fort Nelson, etc.
However the one exception of fresh real good produce and fruit remote wise within Alaska is available at the IGA store in Delta Junction, don't know where they get their supply but it's fresher than any store stocked in Fairbanks.
If one does not carry a cell phone like me, while in any Canada Walmart stores, stock up on the Datawave phone cards that are a great bargain to call anywhere within Canada or the US, the only catch is once activated they must be used within 6 months, so it's use it or lose it for remaining minutes....they still have payphones in Canada, more so than in the US or Alaska for that matter.
Other than that, many have posted consumer goods are pretty much widely available almost anywhere along the major small and large towns, just stock up on essential goods that you feel will not be available abroad.