I spent 5 weeks out of season with an Avis Mazda sports car (which we took over to the South Island - Waikatomo, Rotorua, Auckland, Nelson, Christchurch (beautiful evening drive down the coast), Dunedin, Christchurch, Mt Cook Glacier, Queenstown, Doubtful and Milford Sounds (a must) - all the way to the bottom to Invercargill (like Morecambe but great Bluff Oysters), Alexandria, Greymouth (where the accident was) and its a long drive up the coast to Fox Glacier, back to Malborough and Nelson, over to Taupo, Gisbourne/Coramandel, back to Auckland and a wee expedition north.
Take your cameras! The ex and I went through 70+ rolls of film.