Derived from the boring history episode
Bushcraft a roundhouse. The shape helps with wind. The fire is central. The mutual body heat helps. The flooring is dried and dead leafs/pine/etc. The thatched roof allows smoke out but holds some back till it can be absorbed above. This keeps out insects and keeps heat in.
Camp with just a brat (Celtic cloak) and leather bag of essentials. Go somewhere safe on a Friday evening to camp and do this. The brat can be converted to a tent with stakes.
Dried meats, dried cheeses, fire starting kit including, flint, steel, and char cloth. Dry tinder in a bag carefully constructed from woven Build an underlayer of bedding out of bracken, dead and dried plant material, heather, fern, fibers, etc.
Build a fire and place stones in to warm them. Place them amid the sleeping area. They can discharge over night after the fire dies, amid the sleeping area.
The Celtic point is bodily conditioning, survival skills, naturalist skills, and spiritual growth, memorization, and reflection. Hypothetically, you could adapt over 3 days, or take a Monday off to adapt over 4 days. You could chain this with fasting.