1. The Bay Area as a whole has pretty good public transit.
2. There are plenty of cheap single room rentals outside of SF.
3. She wasn't living on public property. It's private.
Sure. It's just the knee jerk reaction that the person not paying rent is the one "screwing someone over" and not the landlord who has collected illegal rent for years and gets to skip out on the responsibilities that entails.
I'm pretty sure that was the best he could at the time. If it was possible, he probably would have evicted her sooner. It's also not like she's completely helpless or didn't know about the home being for sale, and there are plenty of cheap rooms near public transit for rent in the Bay Area.
At the end of the day, it's private property. She's not entitled to live there if the owner doesn't want her to.