We took DD to NZ when she was 11 mo. We drove from Wellington to Auckland, stopping at different places along the way, and staying in motels.
TBH I wouldn't do it again. The roads are very slow (no motorways) and a journey that looks on the map as if it will take a couple of hours can take most of the day. We had too long in the car and not really long enough at any of our destinations.
My mum did the same journey on a bus and got to see much more than we did.
We went to NZ in October with a 4-year old and 18-month old. We hired a Maui campervan and it was fine for us. DH slept with our older daughter in the double above the cab, and I shared with the baby at the back. Towards the end we all slept comfortably together at the back (king size bed).
We started off in Auckland and went to Whangerai, then KeriKeri in the bay of islands. We only drove for a max of 3/4 hours so we had more stopovers than we anticipated. We headed back down via Orewa, Rotorua, Taupo, Napier and finally to Wellington. The cost of taking the motorhome over to the south island was too prohibitive for us, so we had to drive back to Auckland to return the van.
It was fun in the van, but we wouldn't do it again (too cold, van quite slow and cumbersome), but would hire a large car and stay in motels instead. We stayed in Top-10 parks predominantly (spotless facilities) and De Bretts spa holiday park in Taupo (fab hot spa which the kids both loved). These all have motel accommodation on site too.
I'm not sure about carseats in the vans, it might be the 9-month old + ones only. I seem to recall not hiring cars when the girls were in infant seats , but there are big superstores that sell them cheaply.
I'm very but I hope you have a wonderful trip, we did!!
We're going in February with dd who will then be 8 months! We're just trying to plan a rough itinerary and would love any tips or "must dos".
We will be staying with friends in Auckland for the first few days, then drive south down North Island and will get the ferry to South Island. We'll be staying with friends near Christchurch, but don't need to be with them the whole time we're on South Island.
Campervan - crazy to attempt with a baby or actually quite a practical solution? (Realise it's not a cheap option though!)