I'm on my third back to back season, going onto my 4th in Perisher. Never been to NZ though, I hear the pay is pretty rubbish, but then again, the pay in America is pretty rubbish to.
General tips... money is king, if you can't afford it, don't do it. BUDGET HARD, pick up as much work as you need to. Helps to have as much money as you can horde and try and line a job up in advance.
Washing dishes is sick. Brainless work, but If you find the right place you get to ski all day and work nights, every single day. Free food is a bonus as well.
I guess you could live in a van but it'd suck pretty bad... I'd start looking for places to live and ask whoever your trying to gain employment with if they can hook you up.
But yeah, I emphasize that money is king, your gonna be eating noodles and canned food pretty much everyday and your gonna be super poor, but Its so worth it to be able to ski all year, every year.
Hope some of that helps, good luck man, live the dream!