Just so you know where I'm coming from...I'm 24 and was traveling with 2 other guys...just for some perspective.

Basically, you won't go wrong...it's a great place! We stayed is Vernazza and loved it. It's small, one "road," no cars except for am business deliveries, and everything is small. They have some decent food too. The hike up to the northernmost town is beautiful. If you don't do the whole hike, at least do that part (it's tough though, although we finished from Corniglia into V so that was hardest for us). Corniglia is a pain to get into by train or on the path heading north, but looked like the town itself might have the most to offer without seeming so big and touristed like the two bookends. The southernmost had a great restaurant (for fish). Head up the hill from the train and it will be the first place on the left. Watch out for the jelly fish! We never had trouble in V though.

Any questions, just ask. It's a great place!!!