I think I've posted this before, but it bears repeating. This is a free plan with detailed instructions on building a 160sq/ft (~14.86 m) structure that will work very well as a long term #tinyhouse
It's possible to build these types of shelters inexpensively and securely and in large numbers
Build a few of these and you've got yourself a small village that's easy to support with solar power. Each one has enough roof area to support reasonable power needs