1. Yes. Some of the nicer places are pricey, but not by California standards! There are a lot of crappy places, and some super-sketchy landlords (David Morrison / JetOne LLC seems to be the worst) - but good places, too. The facebook group is the best place to ask about good places to live:
http://www.facebook.com/group.php?gid=47156512637 I live closer to Pittsburgh and drive, which sucks a little, but it's worth it to me for the things I do in that city. I think that most students live in Greensburg.
2. We're having our first club start-up rush after the holidays, so we'll have some clubs by next year. As for night life, you should ask the more local students. Again, fb... We have been getting together informally, and there have been I/M sports every week (soccer in the fall, maybe basketball or indoor volleyball now that it's finally cold out).
3. Some lectures are together. I think I know about 90% of the class by name, 75% as acquaintances, 50% pretty well. I mean, you'll almost automatically make at least a dozen friends, probably, plus the seven or eight people in your PBL group, the ten other people from California, the two dozen you play soccer with, the three dozen in your clubs, the people who live around you, etc. It'll be hard not to know half the class, and social life is what you make it.
I look forward to meeting you all in July!