Not sure is there is any point commenting on this thread or not. Just in case the OP is still interested here is a perspective from a born and bred Kiwi teacher (high school though).
My understanding is that ECE is a bit different from secondary teaching but here's what I know:
ECE education has varying salaries based on qualifications, experience and what type of ECE provider you are planning to work in. It can be negotiated as an individual contract or as part of a collective agreement through a union. I have an Aunt who is in the business if you want more details.
Cost of living: to be fair I have never lived in another country but the cost of living in NZ varies quite a bit depending on where in NZ you are living. For example my three bedroom property to rent in the middle of Kaitaia (a rather small town right at the top oft the counrty) I pay $200/week. I have a large yard and don't have to pay for water. For a similar sized rental property in Auckland Central would be $430+ and you probably wouldn't get the same amount of lawn and would potentially be quite a communte from your work.
I'm not sure about your living situation but over the year I average about $120/month electricity charges which is me blasting the heaters in the winter and running two fridge-freezers year-round.
If you want to get an idea of protperty costs in areas you are looking for work
Buy online and sell with NZ's #1 auction & classifieds site | Trade Me this is a good place to start. It also lists flatmates wanted.
I'm not quite sure what is meant by 'Island mentality'. Like I said, I have never lived anywhere else than NZ, but most of us are pretty welcoming. I imagine it is the same in parts of the US where you have a few who are a bit resistant to change and see foreigners as the bringers of this. Mostly I think you would have no real problems unless you come across some real idiots (which seem to be a worldwide issue, not unique to NZ).
The culture shock might be a bit intense - the Maori influence will probably be the biggest one. But I imagine there will be a cutlure shock anywhere you choose to move, even if it is within the US.
The education system over here has its ups and downs. But according to the Teaching forum on this site it seems that same can be said for the education system in the US.
Hope this helps, and if you have any questions just let me know.