It is indeed hard to strike that balance. I've not properly written up my return statement but based on my experiences I would recommend not trying to do a hugely ambitious project, expect the experience to be social, and, if you're already a senior programmer, expect do to mentoring.

RC is definitely a cool and unique place! One thing people might not recognize if they're not keeping track is that there's usually about one item by a Recurser on the front page of HN.