As for choice of initial tech hub, my vote goes to Pittsburgh. The population size is [roughly] what you're going for at ~300K. The housing market here is great. It already has a tech-friendly local government. Plus Carnegie Mellon is here, ready to feed top young CS talent directly into the autonomous positions.
For what it's worth Pittsburgh was also voted as the most livable city in the U.S. a couple years ago [1]. I might be biased since I live/work in Pittsburgh and take CS classes at CMU, but by that same token it also means I'm speaking with first-hand experience.
[1] http://www.marketplace.org/topics/life/news-brief/its-offici...