Just booked for 3 weeks in New Zealand. Flights and hire car booked, some hotels sorted.
Any hints and tips please share! Planning on landing in Auckland, driving to Rotorua > Wellington > Queenstown. Albiet with stops off in the south island. Not sure on the first stop, but most likely a few days at Mt.Cook for some hikes etc.
As a mountain biker, I'm so excited. A day in Rotorua and maybe a day or two in Queenstown
I would plan to spend most of the 3 weeks in the South Island personally, I found it much more interesting. I travelled in a camper van, so had a little more freedom on time and arriving at hotels, so I would plan as much as possible. It sounds like you're more into the nature and adventure part, so with that in mind:
North Island
Auckland is a standard large city, probably worth a walk around the waterfront but I didn't find it that exciting after seeing the rest of the country (it was my last stop). Plenty to do north of it in
Bay of Islands,
Cape Reinga and
Ninety Mile Beach, but there's no way you could fit that in.
Rotorua is cool for the geo-thermal parts, but again, I didn't spend much time there so maybe others know better. Likewise,
Wellington was a nice city to walk around with a few things to explore, but I found it to be just that, a city.
The parts of North Island I enjoyed most were
Lake Taupo area, plenty of adventure activities there,
Waitomo for the glow worm caves and the hike at
Tongariro National Park on your drive down to Wellington.
Waitomo is maybe a bit out of the way on a drive from Auckland -> Rotorua -> Wellington, but there others are all essentially on the way.
Other notable places are Mount Taranaki, The Coromandel, Napier, but they're on the coasts and way off your route.
South Island
So much to do here, my girlfriend and I spent 4 weeks out of out 6 weeks in the South Island.
Arriving in Picton on the ferry you could go
west and check out
Abel Tasman for some hiking and kayaking, probably some of the best beaches in the world up here. It's quite a drive and off route though, so it would eat up a few days of your time.
You could go stop off in
Renwick on the
east coast and do a Marlborough wine tour, my girl and I spent Christmas Eve doing a cycle tour of the wineries doing free tasters at each, great fun and great memories. You could also then drive on to
Kaikoura and do some whale watching if you're into that, we did a flight tour which was good fun and a bit different to the busy boats. Hanmer Springs is also (kind of) in that area.
I guess if you're planning to head to Queenstown as quickly as possible that you'd end up driving the whole way down the west coast, but if you can find the time I would suggest the first half on the east coast route via Renwick and Kaikoura if those things interest you, then you can drive onto
Christchurch as well. We found Christchurch a bit... dull and empty, but probably to be expected after the earth quakes, and it's interesting taking a walk through the city and looking at the destruction. We stayed in a prison converted into a hostel there, would highly recommend for something a bit different.
We actually flew into Christchurch, and we first drove east to
Akaroa. Really cool place with flowing hills and countryside and seaside towns. Then we drove back west and into the mountains through
Arthur's Pass before driving down the west coast. If you do that, I would suggest making a short stop in
Hokitika and checking out
Hokitika Gorge (google it just for the colour of the water!) and then you can drive on down to
Franz Josef Glacier and
Fox Glacier. We walked out the glacier ourselves, but also planned to do the helicopter drop and glacier hike, unfortunately it was too foggy the day we booked and we didn't have the time to stick around for it.
From there you can drive on through the
Haast Pass for some great mountain driving and rivers and waterfalls. It's a long drive, but when you come out the other side and arrive at
Lake Hawea... wow. You can then drive on to Wanaka, which IMO is a better, but smaller Queenstown, however it doesn't come with the bungee jumping and a few other adventure activities you get in Queenstown.
You mentioned Mt Cook, so I guess from Wanaka you'd drive up to Lake Pukaki (again, the colour of that water

) and then on to Mt Cook. You mentioned a few days, I'm not sure if there's that much to do to spend that long there, but we just did the 2/3hr hike out to the glacier and back again and that was plenty for us. From there we drove on to Takepo (or Lake Takeapoo as we called it) and then down the east coast through Timaru and Oamaru which are cool little towns.
But.. I guess you'd drive back down to
Queenstown. You've obviously done your research on that so I won't cover much, but I did two of the bungee jumps there (do it!), there's the Shotover River Jet if you fancy that, there's mountain biking which I'm sure you're aware of. I'd also recommend checking out
Arrow Town, I think you can even cycle there from Queenstown, might be something to look into. When we were in Queenstown we camped every night on a small, deserted beach opposite Pig and Pigeon islands, really nice drive out there I'd recommend (just the highway, not to the actual beach). Got the camper van stuck in the sand one day but luckily a boat owner came down the next morning with a tractor and trailer and helped us out!
If you can find the time I would definitely recommend the drive down to
Te Anau, and then up to
Milford Sound, breathtaking place. You could do the Keplar Track hike near Te Anau as well.
We also drove down to
Dunedin (probably my favourite "city" in New Zealand (excluding Queenstown, Wanaka and Taupo - they feel more like towns)) and the
Catlins (some nice forest and waterfalls).
Quite a lot in there, but maybe some ideas for the drive down to Queenstown.