I've built a new home, NOT off-grid but capable of a limited autonomy and I'm FAR less optimistic than the author: first of all I'm living far south (French Alps of the south) so in a far more p.v. friendly place, with less cold for less time in winter and still a circadian thermal Δ that makes cooling needed only when the Sun shine. It's not a cabin but a home so with far more room for equipment.
For the home I see I need to double my p.v. to 10kWp JUST to achieve a bit more than 50% self-consumption of the year, from 72% maximum in spring/summer to 35% of November-February. WFH to recharge A BIT from p.v. my EV with a realistic relative autonomy I need around 10kWp three phase, not single phase. Witch means three time the plant and it's costs, space etc. Still NOT reaching autonomy.
Not counting the usable life of LiFeP storage and NMC cars...
With my actual setup I can POTENTIALLY halving by home storage operation life be autonomous just from late May to September being VERY attentive in all I do, without counting the car. With a theoretical 10kWp x 3 I might be reasonably autonomous also for car (limiting my trips much) just from June to August. Actually my time-machine is offline and my body live 365 days per year, regardless of the season and actual hours of Sunlight or heating/cooling needs... Oh, and I also need to eat, being unable to create my own food out of my land (except for VERY limited amount of veggies, fish and meat casually hunted in a limited period of the year)... Oh, and of course I need many gears, starting from p.v. who is built by factories unable to run on p.v. themselves.............