Tony I only ever went to the "Akas" a few times on a bike and a few times later with the 4WD club. The other Brent up here "Muz" spent a lot of time up that way in the late 70's early 80's. I don't know the roller coaster but he remembers it.
I rode mostly around Wgton, Moa point, Wrights hill, the steps to Massey memorial!, the south coast (my cousin had a batch at Karori stream mouth). We even had our own personal track on the hills above Houghton and Princess bays.
When I had my TL250 the entire coast of Wgton was a trials section, I would ride for a full day trying to get right around the coast without riding on the road or footpath, some of it got a bit hairy and once ended in a swim