While perhaps ideal, this isn’t always a practical option for all travelers. It can cost thousands of dollars to purchase a vehicle, on top of the cost of your plane ticket to get there. Add to that the cost of fuel, maintenance, insurance, camping gear, and potential parking or illegal camping fines. I think this option is best for those traveling as a pair or in a group, so you can split the costs.
If you don’t have the travel partner or the budget to make that happen, don’t rule out traveling New Zealand by bus!