If that video is where I think it was, the counties have zoning laws that put limitations on what can be certified as a residence. Typically a minimum of 600 sq ft, which this house met, but many tiny homes wouldn't. They require a well and septic system. This video mentioned having that requirement. He had previously lived with a composting toilet, which is a viable solution but that location required them to have septic.The key in my personal paradigm is being in a heavily wooded unincorporated county with relaxed regulations and an even more relaxed enforcement protocol. Basically the type of area where someone comes to your gate or sends you a letter stating they want to "inspect" your property and you say, "Get a warrant," and they say something like, "Oh nevermind," shake your hand, and leave.
If (((they))) insist then you show them the "fake" front of your property with your livable RV set-up (with self contained on board septic), while avoiding your multiple, spread out, tiny home like structures that are either wholly or partially underground (which necessitates owning a 20K backhoe) and or camouflaged from aerial surveillance.
The true definition of off-grid for me requires no well (rain catchment and at least one year round flowing creek), no septic tank (composting toilets and grey water catchment/filtration), and no public utilities, especially electricity (solar, propane, hydroelectric). In addition there are plenty of very nice areas in America where you can still get 40 to 100 acre parcels of land for less than a thousand dollars an acre. This will not change in our lifetime.
Also, their location has an HOA. It's probably a ranch that was broken up into 35 acre plots. The HOA requirements will usually not allow people to live in a long term RV setup. There are some areas full of RV type homes and shacks, and they tend to be quite rough. These HOAs are designed to keep the riff raff out.
Does NC really have land with no zoning requirements like these, or is it a case where they exist, but are not enforced? If this is the case, there's always the risk they could start enforcing them a few years down the road.