There are of course very few rooms in that area and late November is prime season (quite nice and warm there while still cold in the southern part); I can believe Abel Tasman being sold out already. Have you considered Bed and Breakfast stays? I've used http://www.bnb.co.nz/index.html with good results. In some parts of NZ there are only 100 rooms of all kinds in a 50 km radius -- so one group can sell out half the room supply. Of course the lack of development is a large part of the charm ....