Rich,
It is unusual to take 'the simple life' to that extent, but not extraordinary. The "beating the system" and preparing for the apocalypse aspects may simply be rationales he offers for not interacting a lot with the rest of society, or it could be his real motivations.
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Regarding "living off the grid", strictly speaking it merely means that one is not connected to the utilities (and increasingly, communications) grid. It doesn't mean that you don't have electricity, merely that you generate your own in some fashion AND are not connected to the grid. Many folks generate their own while remaining connected, either because they don't generate enough, they want backup, or they sell electricity to the grid. Ditto for water and sewer. Does having a septic tank mean "you're off the grid"? Well, it means you're off the sewer grid. Nor does it mean that you don't participate in the modern economy, don't socialize, etc.
Now, many people will take it further. They may forgo any energy sources that are outside of their control. So, hydro/geo/wind/solar on their own land are good, but grid/generators not so much. Wood/coal are the primary fire sources, although some will consider oil/gasoline/diesel/natural gas/propane as acceptable for the short term. Food, a combination of stockpiles and grow/catch/trade. They may farm, or at least have a vegetable garden. They may farm using a tractor, and/or draft animals. They may eliminate modern communications tech. They may be hermits. They may homeschool. Others "live off the grid" while commuting to work in the city, dropping their kids off at school on the way and picking up a movie at Redbox on the way home.
The motivations for going off the grid are almost as numerous as the degrees of off the grid one can go. One motivation that's gotten little mention is an awful lot like what motivates many people here to work wood. Metaphorically speaking, living off the grid is a "hand made" life, not one made in a factory. The virtues of simplicity, self-reliance, lower cost, authenticity, personal design, and by gosh, can I do it? (note that realizing these virtues can be as elusive in living off the grid as in woodworking.)
So remember, as you're buffing out the last section of the new dining room table that you hand crafted alone in your shop, using wood felled by an artisanal lumberjack, you've gone off the furniture making grid. When you stand back to admire your handiwork, as the notions for the next project swirl about in your mind, ask yourself: "Am I crazy?"