You're misunderstanding how popular what you want to do is. There are 73,000 NZ Motor Home ASSC members. Lots of them live permanently on the road. There's 10 times as many tourists every year. They absolutely shit up every single vaguely scenic place in the country.
There's basically no such thing as an isolated beach or mountain track that you can drive to and stay, by yourself. It's almost always going to be signposted that you're not allowed to, and if it wasn't, there would be 10 campers living there. There's also always going to be a nearby doc site that's intended for you to use. Caravan parks have shared kitchens, showers, laundries, a grumpy old cunt who lives there, etc. They aren't great unless you want a hot shower. Doc sites are 95% of the time in an extremely nice place, with basic toilet blocks and unfiltered water, maybe cold showers, maybe bins and that's it. People are friendlier at doc sites. The rangers you meet are always gcs. You pay $8- $13 a night pp. It's worth it because of how nice the sites are, not the facilities. There are a few free sites and they always suck.
Locals aren't getting butthurt at you, they're getting butthurt at the thousands of identical people who all had the same idea. http://www.doc.govt.nz/parks-and-recreation/things-to-do/camping/conservation-campsites-brochure/
Get a bicycle if you want to stealth camp, logging roads all have locked gates, you can lift it over them. >>1252471
nothing wrong with a harmless bit of fun m8