Have 16 days in NZ in January with wifey and three teenagers. (Yeah, I already know it's not enough time). So far all I have arranged is a flight into Christchurch, and a flight out of Auckland.

There's more than enough info available on the expensive andrenaline activities, but that's not what my kids like. We're more after nature gems that I'd otherwise miss. Seems there's some great walking at Wanaka. What else should I know about?