My parents recently visited a Yoga course at www.prana.co.nz
I’ll directly quote from the site.
“A unique natural environment of park like setting close to an unpopulated, just 5 minutes walk iconic untouched-by-man beach.
The large 100-acre natural site and coastal positioning is magnificent. Nestled between rock faces covered in magnificent ancient Pohutakawa’s and pristine dune beach with 165.25 million sq.km of the Pacific Fresh Air System in front of it.”
it’s 2 and a half hours drive out of Auckland (this is where you all grumble cos your a bunch of lazy bums )
now my folks inform me that the place is run by old hippies who are very nice.
the the lodging area there is a large hall building but the sleeping arrangements are actually in old hippy caravans 
(so for fantasy people could sleep in tents somewhere else on the HUGE land plot) and if you wanna run something modern you could disguise it as a road trip - post apocalyptic (hint hint Brian) a Trailer park.)
Anyhoo the site again is WWW.Prana.CO.NZ
I have no idea how much hirage costs will be but thats something to find out I can’t expect that they will be through the roof as the place is pretty much a land lease situation and gas.