Yeah, just play for long enough and you'll crash into a randomly generated mission to rescue a survivor, I've only found 1 survivor, but I think I have like 6 buildings, so at least two of them are going unused at the moment. I still don't really understand the town concept as a whole, I just build the buildings as soon as I get the scrolls for them, and beyond that, I just abuse the Opal Crystal for infinite enchants while I'm trying to improve the RNG qualities.