Thanks all for the suggestions and sources!
It would help if you specified whether particular sources are simple download & play, or have barriers that may require technical compromises - thanks in advance.
I never got into Larry Niven, but love his collaborations with
Jerry Pournelle.
Brian, can you recommend a specific Niven novel to get started?
Thanks for the Jack Reacher tip. I've seen & liked the first movie, so have added that to my mental list, when I'm better set up for audio visual stuff.
Speaking of "juvenile" books, Heinlein's are a great place to start in his books. Many of his late "adult" books are, um, YARC.
Given that many here are ecology/sustainable/etc leaning, his two juveniles that you'll most enjoy are
Farmer in the Sky and
Tunnel in the Sky.
His greatest eco related novel was his
Hugo Award winning
The Moon Is a Harsh Mistress (an "adult" book). It's also very political, but thought-provoking not wing-nutty.
His adult novel with great advice for would be van dwellers is
Starship Troopers, in particular, the protagonist's attempt to join the K-9 Corps.