I'm working with a self-drive tour company in New Zealand for arrangements. They will have everything finalized when I confirm what I want to do, including securing the rental cars and ferry transfer. The longest drive I think will be Rotorua to Wellington but then I have the next day off from driving anywhere far. The final few days of the tour will be spent in Queenstown before I depart for home. I'm hoping that I won't be overtaxed within my time frame...