I am running a slightly modified version of the challenge now. It's great fun, as it requires a completely different approach than all the other starts available in the game. I am making notes as I go and plan to create a separate thread once the challenge finishes (i.e. summer season starts, or my character dies).
The modifications are that I am using mods, as I installed the excellent BAC mod not long before creating the character and just could not bear removing it. Due to its complexity this mod requires a large set of tools to really take advantage of it, so correspondingly it has very little impact when you start with no tools at all. Then, at the very start you are put on the wilderness map and an indication of your location is displayed; I took the liberty of checking it. My imaginary backstory was that my character Onosho was attacked by particularly greedy robbers while traveling, and it seemed natural to assume that he would know his rough location from the pre-game course of his life. (Turns out I started in western Sartola.) Lastly, I misinterpreted Nekot's rules, and started using the big map (F6) as soon as I reached a village - in fact the rules only allow traveling on the wilderness map, not the use of the world map. But I have been doing this for a long time now and will stick with it.
So far the challenge was bigger than usual but not overly great. Soon after starting I discovered a large area of spruce and pine mires, teeming with cloudberries. That kept me fed and watered for a whole month. As the berries were about to wither I stumbled upon a mountain, from which I noticed a village nearby (you are allowed a peek of the wilderness map from the top of a mountain). It turned out to be a Seal village. In there I found a wounded adventurer, who promised to reveal a location of a treasure if only I recover his trident. I did this, but the treasure turned out to be buried in the ground on an island somewhere off the Seal coast. So I went back to Sartola in search of a metal shovel; I haven't found it yet, but managed to buy an elk fur just a few in-game days ago, so at least I am now fully clothed at last. I have also just passed the midwinter point.
Keeping warm was never much of a problem. I carry a stack of torches and make sure one is lit at all times. While I was still out in the woods I would cut down a young tree every evening, to make sure that the fire will last until I wake up, then use it to light a torch first thing in the morning. While foraging I would light a smallest fire next to a clump of berries, and the fire (and once it burnt down, the embers) would keep me warm surprisingly well. I only got really cold when walking longer distances.
As it got colder, one fire was no longer enough to keep me warm. So I took to lighting three fires instead, with great results. Once the berries withered, I could no longer keep myself warm by foraging next to a fire, so instead I started gathering branches next to a fire. The first time I tried that, my own fires promptly set the pile of branches alight and I was badly burnt as a result. From that point on I avoided further burns by immediately picking up the freshly gathered branches - except that one other time when I forgot to pick them, and got burnt again. Burns are surprisingly serious and potentially debilitating: I lost the use of one arm for a week as a result. Do not set yourselves on fire. I did this so you no longer have to.
Then I found some Sartolais villages. One had an axe for sale; the other, an elk fur. Both were well stocked with grains. So I borrowed the axe to make some fox traps, which I used to buy a bag of grain. I ground it into flour, and sold the flour (and some small items) for two bags of grain, which I ground again. Once I bought up and processed all the grain from this village, I moved to the one with the fur on sale and continued the process there until I was able to afford it. Fittingly, I finally bought it on the last day before midwinter point.
So here I am now. Many more (mis)adventures remain.