I have to admit that primitive farming is initially a better option than hunting and gathering because it is able to sustain higher populations, though anyone that farms will be highly vulnerable because of their immobilities. If you are going to rely on farming in a post-collaps scenario, you either need to be part of a larger, well organized, group or you need to live pretty far away from everyone else, and if you live that far out in the wilderness, there probably won't be to many other hunters to compete with either way.
I think either subsistence farming or hunter gatherer survival are far tougher and more brutal ways to survive than the vast majority of those inhabiting developed nations really comprehend (which is also part of my argument for limited numbers being capable of making it in the refuges/niches I identified).
No matter what you are doing, you will need to be part of a group to do it effectively. An individual or handful of people can at most merely survive, only a group can really go forwards longer term - and I'm sure the advantages of being in a group don't really need stated even taking a shorter term view.
I know this thread is meant to be about America - so I think America would make a good case study for this question. How many people living there can really adapt to the loss of fossil fuel powered infrastructure, air conditioning, etc. - and make the long hike into the canadian wilderness and manage to survive up there? This assuming a fairly abrupt climate change scenario where there isn't a lot of time in which to build new infrastructure and relocate people in an organised fashion etc (one would need decades to do that I imagine?). In any case infrastructure is also being negatively affected already even where it exists in the northern regions (as permafrost melts, coastlines erode, etc).
Let's suppose that the fossil fuel from overseas has stopped as other nations have failed, the domestic supply is increasingly exhausted (and fracking is a short term yield, so that isn't a long way away really), that agriculture is failing due to the climate in large sections of the country and problematic in others due to fading manufacturing and distribution channels.
How will the bulk of the population respond? Do we really think they can leave the cities and strike out into the wilderness? Or do they huddle together into desperate and dying masses perhaps looting the surrounding area but unable to go further? In my experience the majority of people in developed nations today don't have a hope of going out into the wilderness. Many of them don't even know how to grow food (in favourable conditions, let alone those of survival). Many can't comprehend the simple idea of killing their own meat. Local resources (both domestic and wild animals) will of course be rapidly exhausted as pointed out (simply too many people and too few animals).
In this way - again - how can large numbers of people move north? To do so they must pass through a land already turned into a resource desert? How easy would it be to travel thousands of miles from the south to the north passing through a landscape already stripped barren and populated by the most tenacious and desperate who survived there that far? How can a lot of people make that journey? Surely only those already fairly close to the northern area can easily move into it? (and even here I think the softening of civilisation will make it a lot harder for most of those from affluent nations - which as far as I can see is most of those bordering the northern lands under discussion).
It depends greatly on the rate of change of course. If the rate of change is slow enough human society will try to exploit and develop the north - build infrastructure - let people move in - etc.
Right now I would argue the rate of climatic change exceeds the rate at which the northern areas are being developed (and climate change is only likely to get faster, and that developing those regions becomes ever harder as we have more and more damage to resolve to the existing developed regions - where we are also already falling behind the curve).
Also, I question that most people are well enough informed (especially in the US) to understand what is happening or why they should head north... if the Americans among us will forgive the cheap shot.
