I live in Colorado, and the rents here have been rising like crazy for years. I wanted to move into an RV for a while and then save up for a tiny house, but after looking into it, I found the same problems you did.
Backyard living is a possibility out here because we have some counties that allow detached dwelling units in yards. I lived in a 450 square foot garage apartment in someone's back yard years ago, and it was awesome (except for the whole going to the laundromat thing). I think I could find someone who would rent their backyard for a tiny house, but the idea of setting up plumbing and sewer connections is daunting.
With an RV, there is nowhere within city limits you can park one and sleep in it, unless you're paying for RV parking, and RV parking costs almost as much as rent.
There's been some talk out here about building a tiny home community, but I haven't seen much action yet. https://neighborland.com/ideas/den-a-tiny-house-community . There are also some wonderful people building a tiny house village for homeless people, so if rents keep rising, I may end up there. ;-)
Let me know if you have any luck in your quest, and I'll get in touch if I have any luck in mine.