Just come back from living there for a year. We did a tour before we came back. The South island is very scenic, Franz Joseph and the Fox Glacier cool places to visit – we didn’t get to go on the helicopter ride but if weather is good definatly worth doing. Not much to do in Franz Joseph town etc.. it’s self apart from indoor ice climbing (quite cool) tranz alpine train from Greymouth to Christchurch definatly worth doing. Queenstown is beautiful, and has a luge (tyoe of go kart) on top of a mountain- very cool and if travelling in summer (us) winter (there) good for skiing.
Wellington is beautiful, lots of buildings, lovely gardens and you can meet the one legged kiwi at the zoo there!
The north is not as scenic more beachy, Auckland City ok, sky tower good – recommend new sky walk and tower jump if adventurous. We lived in Red Beach/Silverdale/Orewa very beachy local park/beach Shakespear Park BEAUTIFUL! Auckland Zoo is FAB – hand feeding the giraffes was superb!
If time and you like trees visit Tane Mahutah VERY BIG kauri tree!! Cape Renga the most Northern Point of NZ is super fun!
do a coach trip (see below for details of travel agent over there)
Other good places to visit: Kelly Tarltons (near Auckland)
Antartic Centre (near Queenstown (think) airport), Very cool lots of penguins and you get to go in a snow room whch has snow storms minus 16!!
Don’t do any guided tours of Lord of Rings there is a place in Queenstown that you just pay $15 at toll gate and you can drive round scenery yourself!
One way of doing it is to fly to Auckland spend a few days there and go to see a travel agent in the city tell them what you enjoy doing and let them build an itinary for you we used The Flight Centre on Shortland Street, Auckland city centre, they were VERY helpful! Internal flights would be a lot cheaper booked whilst over there! and they can get better deals for you!
Hope this helps
If you want specific details I may be able to dig out my itinary and help out some more PM me if want.
Enjoy your trip it is a beautiful country xx
Sorry for any spelling mistakes etc.. very late very tired YAWN!