Not everything ran according to plan when I visited New Zealand in February 2006. The weather and my carelessness denied me some expected highlights. Nonetheless I saw some great scenery, saw some of the endemic wildlife, and spent good times with my wife's relatives in Auckland. They showed me round Auckland, places like 3 Kings Hills which is now only 2 hills as they used the third for building material. That was as important as anything, I like travelling distance and meeting friends.
The weather is changeable - when it rained it rained and blew. Boat trips (like I had planned to Tiri Tiri Matangi) can get easily cancelled. Mostly the weather was fine, lovely clear air, you can see for miles, but not as hot as parts of Australia.
I stayed in quite a few homestays and very pleasant experiences they were too. They're like B&Bs but you're even more staying with the host family, you eat with them, you don't have keys. Some of the homestays were luxurious. A good way of meeting the locals who were very helpful.
Food-wise I found the potato-like Maori vegetable called "kumera" very good, and also quite liked feijoa juice. Plane food on my 36-hour journeys was dire - I barely ate.
Most of the roads in New Zealand I drove along are small winding country roads. Only in Auckland did I encounter motorways (which were congested.) The road system is good with some challenges for the visitor. There were a number of bridges with a single-lane, and even some where trains also shared the same space! At the time of my visit New Zealand had a law in effect where people turning right have priority over people turning left (they drive on the left.) I didn't get this always correct. You can also overtake on the inside.