The craigslist bike will be too small (I'm 6'4", and that's the size I ride), but for the money, and the riding you described, I'd probably buy it anyway. Used tall bikes are really rare, and on that one it looks like there's room to raise the seat, and the stem can come up a little, too. New seat posts and tall stems aren't cheap, but they are available (maybe $40? Haven't bought one in awhile) if you need them. Plan on new tires and a minor tune-up, which you can do yourself with basic tools