This trip Up North, run in association with the Kauri Coast 4WD Club, is always popular so it's best to get in early. An bonus of the Jan 19th-25th event is that it returns to the stunning silica sands on the east coast; this alone is worth the entry fee. The proposed route goes from Dargaville, along beaches and through forests, following some early settlers' tracks. Safari-goers camp overnight at schools and a golf club and meals will be available each night.
Get in touch with Chris or Leanne Kemp, 0-9-434 6005; 329 McBeth Road, RD9, Whangarei 0179, or email firstname.lastname@example.org. Here's a post from a couple of years ago with a picture of some action in the silica sands.