The interesting thing is that if the apocalypse or "doomsday" is due to climate change, then we don't know yet where the safe places to setup are. Somewhere that is warm now could be cold or flooded or infested with some new pest in the future. Any plan that involves being root to one place seems doomed to failure in a true catastrophe. Seems to me that a better plan would be weapons and unarmed combat training, basic first aid and knowledge of edible plant species throughout the world. If you want to hoard something, hoard containers that can be used to purify water and matches/lighters/flint. Of course, anything I say can be taken with a grain of salt since I'm purely a city boy!
My family is from rural eastern Washington, and we have a cabin that is about as "off the grid" as you can be while still having any kind of modern comforts. We've got an outhouse (a septic tank as well, but let's leave that out because of the maintenance piece, even though it was installed and has been maintained by family members for years now), a well, tons of electric blankets and really basic winterization, and enough room on the sleeping porch for 5 beds. There are also plenty of weapons there since it was built at the turn of the century and has been used by avid hunters for nearly 100 years now. We've got two generators and every tool imaginable (accumulated over years of visitors bringing/buying what we need to fix/upgrade the place)
We'd need solar panels (which don't pay off nearly as fast in a forest that has a brutal winter) or a windmill (surprised this wasn't listed as an electricity option - some neighbors up there have one, and while it isn't a replacement for modern electricity usage, it more than powers their electricity when they aren't there - a good start), and land for growing our own food (although it is in a forest with lax hunting laws that has wild edible vegetation, and on a lake filled with fish, some predictability would be valuable).
That's the original cabin. The new, more modern one that we built recently has an indoor fireplace and better winterization, but it likely requires more electricity and is connected to a public water source (should be easily remedied post-apocalypse since it is right on a lake).
Escaping to the country isn't a good plan. During the financial crisis of 2008 I thought it be a good idea to read about the financial crisis of Argentina during the 2001 crash and what it ment to students/poor people, the middle class in "Surviving Argentina". In short: "On the country-side" no one can hear you scream. A lot of sh*t went down. The books a good read, I even took up the some of the advice and now no longer need lenses or glasses with build-in contact-lenses inside my eye. My house is strengtened as well, and I studied Krav Maga for a few years. Always nice to know a little bit. I liked the first lesson: If you can walk away out of a situation, do it and screw your "honor".
The article doesn't spend much time on it, but it does mention the necessity of weapons to defend yourself. I read the article more about living off the grid today, which would set you up better than the vast majority of those should the apocalypse come to pass. It's pretty much impossible to totally remove yourself from the grid without moving to the country in the modern era.
You're right that this may not be the best possible disaster prep if you are simply preparing for disaster (and don't plan on going off the grid unless totally necessary).
If the "doomsday" event is gamma ray bursts from within the Milky Way galaxy aimed straight at Earth, extraterrestrial invasion, or a massive meteorite impact, then kiss your a$$ and your $137,000 goodbye.
I plan to organize with my neighbors and cooperate to survive doomsday. It has been a proven effective method in the aggregate for the history of the world. Lone survivalists have a pretty dismal survival rate.
Depends on where you get your land. My family's cabin is in a forest in eastern Washington that could probably sustain hunter-gatherers. The Great Plains, however, probably could not (basing this on Native American tribes being more sedentary near my cabin than the middle American tribes that were more transient, as well as my limited knowledge of what grows wild on the great plains).