My husband and I are traveling to NZ in Feb.-Mar. '13 and are flying into Wellington, then ferrying to S. Island, exploring for several days, then flying from Dunedin to Rotarura and exploring the North Island. We need to find a reliable and economical car rental company that allows to drop a car in a different city seamlessly. Also, it makes sense to pick up the car after our ferry ride but then we'd have to rely on public transportation from the airport to our B&B and while in Wellington. Any advise?