I'm packing my bag (a carry-on) and preparing to head off to New Zealand for two weeks. The challenge: I'll be arriving on the first day of spring and traveling to many different regions (including a beach and a glacier), so I've been advised to pack for "every season." I have a short connecting time and a change of airline on my international flight, plus a domestic flight from New Zealand's North Island to their South Island, so it makes the most sense to do carry-on only. How am I going to do it? By following these tips for packing everything I need into just a carry-on.