What a great trip you'll have - have you been to NZ before?

If you're heading to Taranaki I recommend visiting Tawhiti Museum in Hawera, it tells a great history of the land wars between the Maori & white settlers. If it's a clear day I suggest driving up to the ski field car park on Mt Taranaki & look out inland towards Mt Ruapehu & Mt Tongariro - if you're lucky you'll see both.

Also, if you've never driven in NZ before you may get a shock regarding driving times - due to the hills, corners & lack of dual lane roads it takes a lot longer to get from A to B than it does in Australia (unless you live in Tassie in which case you'll be used to the hills & corners )
You may struggle to get to all the places you want to visit in 8days. Especially in a camper which will likely struggle with some of the hills. We had a budget hire car in January & were shocked we made it lol.

It is a beautiful country & you will have plenty to see & do. Have fun!!