You can’t travel to NZ by car or bus, at least not unless they can also float or fly (sorry, just had to say it).

Getting around in NZ is pretty easy, but public transport isn’t great, you’d be better off renting a car (one of those rent-a-dent deals) which means your independant and can move on whenever you like.

There are lots of camping opportunities, and the weather should be ok at that time of year so you could easily pack a tent in the car. There are loads of hostels too if you wanna do things a little cheaper than hotels/motels etc.

You’ve got 4-weeks so you could cover a lot of ground, the regular tourist trail is Auckland (city/party), Rotorua (scenery), Waitomo (caves), Wellington (city/party), across in the ferry to the South Island, down the west coast (scenery, glaciers etc), Queenstown (scenery/party), maybe Fiordland (scenery) then finish back in Christchurch (party).

But there are so many other things to do along the way, I’d go for the hostel option if I was you and ask staff and other residents what the cool local stuff to do is, and just take your time

I occasionally stay in hostels here in NZ myself, and I’ve stayed in loads of them overseas, I’ve found the kiwi operators pretty helpful by comparison.

The best way to travel is to either rent a car or a camper – it depends on how you like to camp.

As for where to go… we’ll there are tons of options. I’ve spent most of my time in the north and have only been to the south island once.

Anyway, here are some options in the north:

Auckland – largest city, Auckland museum

Wellington – capitol city, Te Papa

Northland – sub-tropical, lots of beaches

Rotorua – Geothermal area with a strong Maori presence

For me, it’s just fun to drive around and go from town to town, beach to beach. There are hiking trails and camping all over the place. Larger coastal towns will often have kayak rentals.

Bring your camping gear, your appetite (the food is great) and a sense of adventure.

Here are some of my photos: http://flickr.com/photos/inkbase/tags/newzealand/

Make sure you see some of the South Island as well as the North Island.

Some highlights in the South Island.

Marlborough for wine tasting and perhaps kayaking in the Sounds.
Nelson for culture and perhaps up to Golden bay for the best beaches and waliking tracks. You can go kayaking here too.
The West Coast for scenery. Investigate a guided day trip up Fox or Franz Josef Glacier.
Kaikoura for scenery and whale watching. The name means “eat crayfish (lobster)” you should do that here.
Christchurch has a good museum and Antartic centre. Probably a bit of nightlife there.

Definately rent a vehicle of some sort.

Well I rented a car and it was really the best way to do it.
Make sure you see both islands.
One month should be enough to see most of it, it was enough for me and I stayed a few days in several places.
There are lots of cheap, clean Motels and Hotels so there’s no need to book in advance.
Be sure not to miss Milford Sound, Franz Josef/Fox Glacier, Christchurch, Queenstown and Dunedin in South Island.

Take a bicycle, we did it and stayed 3 months on these beautiful islands. I recommmend the West Coast, the East Coast – since there are no tourists, Coromandel, and and and