You sound like you have the right attitude anyway. I know it's probably something you don't really want to have to consider, but if things got too difficult, maybe your wife could go out and work for a while - just to see you through the hard times.
Also .... have you not considered taking all your 'stuff' with you. We've looked into this subject quite alot and it does actually work out to be the sensible option. A sole use 20ft container will cost in the region of 3k to send out to NZ - would you be able to replace everything for that price? Just a thought - I'm sure you'll mull everything over a million times and it will all come good in the end.
Diny