whoops sorry for the late reply.
Arthurs Pass is in the south island about 2 hours west of christchurch.
if you're flying you'll get into to Auckland. Hitching is really easy in NZ though you still get the surprised looks from people at seeing hitchers.
Also, I manged to bargin my way on various little fishing boats across the islands...weather can be tough. I hid in the boot of a car on one crossing once, and vowed never to do so again...three hours man.
Your not going to be able to hop any trains in NZ, I lived there eight years, and never saw any freights, and, well the place is not as liberal as it makes out to be.
Again, mountain bum head to Arthurs Pass...Up north there'sthe coromandel, which is considered the alternative part of the country. Its beautiful and the climate is good, but it's full off awful hippy types (60 dollars on organic dypers.....)