There are two viewpoints to this reply, one from the vantage point of an architect with a couple dozen years of real world design and construction experience as though one of my clients was cabin builder whom I was trying to advise, solely for a cost effective, build – as-you-go, off grid home solution. The second vantage point is that of a fellow prepper, former Army National Guard Infantry Lieutenant, and in my present role as an Architectural Consultant to Hardened Structures LLC, as though the cabin builder were a client to Hardened Structures.
First, congrats on the land acquisition. This is a great blessing. Be so very thankful for three teen boys who hopefully can share the workload. This will be a key to your accomplishing realistic goals. Next, pray, and be super safe with power tools. I have had three architect bosses over my first dozen career years that were missing a finger or part of a hand from a table saw or something. In my very first self-constructed project, the electrician cut his own kneecap off with a Skilsaw.