The missus and I did a week in NZ some 20 years ago now and say yes, do it, treat it as a prep for a second, future visit if you're lucky enough. We began in Christchurch from where we'd booked a VW camper, drove south to Dunedin then across to Queenstown, missed the Fjords as we realised there wasn't time and turned north along the west coast. Choice of glaciers to visit there (we did Franz Joseph) then took a ferry (VW and all) to Wellington. Surreal moment looking ahead to north island and backwards to south island. Then traveled among the lakes, hot springs and other volcanic activity to Auckland. Another highlight enroute was to camp at a small resort where we spent a few hours under the stars in a hot spring feeding a pool the size of an Guildford Crescent.

New Zealand is fab.

One recommendation for Adelaide (where we also visited a distant relative on the same trip) was to take a pre-booked flight in a small aircraft over Wilpena pound about 100 miles north; Google earth it to see why. And surely you should try to spend some time in Cairns for the beaches and the reef which is unforgettable. Also from there take the steam train to Kuranda (tropical) Forest.

Would love to do it all again.