New Zealand Tour
If you hire a car and drive yourself around New Zealand you can get by with stopping at the most convenient hotel/motel you arrive at each day. This is obviously going to be more expensive by about 40% each night but the convenience far out ways the cost. As you are unfamiliar with the route and attractions the time you need for both depends on you and your companions, and another person is not the least likely to accurately determine an appropriate schedule for you.
This advice is conditional upon hotel rooms being available along your route. If it is a time of many tourists wanting rooms you would be advised to have your stays booked well in advance through booking.com.
Also the need for guided tours to the glaciers can be avoided unless they have changed the rules recently. Getting up early I had walked up to the Fox Glacier and seen all I could and been on my way back to the hotel when I passed an escorted group. The signs clearly indicate what you should and should not do, despite a Western Australian family trying to say that their kin who were killed by falling ice from a glacier front saying they don't.
What to see. In Australia we do not have geysers, mudpools, volcanoes as in the North Island; or fiords and glaciers as in the South Island.
So you fly to Auckland. Hire a car and drive to Rotorua to experience the stench of volcanism, dropping in at other attractions on the way. This is where Google is a tourists BIG HELP.
You need to go a bit further south to see the volcanoes.
Then to the South Island. Flying to Christchurch and hiring another car. In this city the Redwoods are a must see at the Botanic Gardens. They have completed repairs and you can see the laboratory where Ernest Rutherford studied at current Arts Centre, which used to be the University. Some parts are still being fixed up.
This was a pretty city twenty years ago and no doubt still is despite the earthquake so there will be other places to see before heading off.
Then it is a case of "GO WEST, YOUNG MAN", or woman. Being able to cross the country in as many hours as it takes days in Australia is a big plus. You will no doubt get down to the glaciers for the night after having seen some of the other things on the way.
If you want to you can join a guided walk to the glacier of your choice. I can't see the point of helicoptering over it – you want to walk on the thing.
You can see one side of Mt Cook.
Anyway eventually you will be glaciered out and drive south to get to Queenstown. Lots of eateries here. A boat to take a cruise on, the TSS Earnslaw.
And then off to Milford Sound next day and a cruise to experience the fiord. This takes all day.
Then back to Christchurch and see the other side of Mt Cook.
From Christchurch fly back to Australia.
If you are into wine you will also want to drive around the top of the South Island and sample some of the world renowned wines. The driver will have a hard time of it.