I am looking at the best way to travel and visit New Zealand. Should I rent a campervan or should I travel in hotels. I don't want to spend more than 2 nights in the same place but my budget is not crazy high!
Campervans are a great way to see the best of New Zealand. There are quite a lot of people out and about in their RVs in both islands, especially in summer. The best brands to go for are Britz, Maui and Kea, and a range of sizes are available - from 3 berth up to 6 berth. Most roads are navigable with an RV - and they'll tell you which ones are a no go (a few in the South Island in particular).
If you pick a fully self-contained van (with a toilet and shower), there's really no limit on where you can go - you have all the freedom and flexibility you want. In the North Island, you'll see lots of campervans around Taupo and Rotorua for the geysers and mudpools, and in Hawke's Bay for the vineyards. Also check out Waitomo Glowworm Caves - if you go with Britz, you'll usually get a discount as they're owned by the same company.
The Interislander Cook Strait Ferry is the way to get from one island to another with an RV, and most people cruise around Marlborough and Nelson for a few days before heading down the wild West Coast New Zealand to end up in Queenstown for all the adventure activities.
There are lots of holiday parks around both islands too if you want to power up overnight, but just parking up in the back of beyond is usually ok too.
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Have you thought about using hostels and one of the hop on hop off buses? I travelled with stray and loved it - although my advice stay away from the big party hostels like base they are pretty grim but some are lovely! Campervans are awesome but bit lonely and expensive if you are on your own and hotels are unnecessary in my opinion when you can get a great hostel for a fraction of the price :)
You can rent a cheaper campervan (imagine a vw wagon with some built-ins) that you can use to sleep in to save money. You'll have the freedom to stop where you want and stay at campsites.
Renting a self contained campervan will generally be much more expensive than simply renting a car and staying at modestly priced hotels.
You can also travel around by bus as well, though this gives you the least flexibility in terms of timing/schedule/places.
It basically depends on your travel style and budget. New Zealand is not a cheap place to travel around. If budget is a concern, you may also consider travelling there during a shoulder month or during low season. Prices are much higher and the places are much more crowded during the high season.