http://youtu.be/HaBeldfNzn4 Whenever helibiking in New Zealand comes up in conversation, I'm usually quick to point out that Nelson and the West Coast are really the best places to ride. The singletrack always starts right outside the chopper door and nine times out of ten it goes all the way to pretty much sea level. It seems that the Westland MTB club and DOC want to push helibiking on tracks like the Croesus and have put together this little vid to showcase it. It's worth noting that there's an alternative descent from Ces Clark Hut that runs down to the coastline and Barrytown. It's technical and only suited to advanced riders but well worth it (just don't try it in the wet). The main Croesus track is still a blast though; it's way faster than the video shows and is great mix of technical and high speed classic miners benched singletrack.
If you think taking a chopper is too expensive, think again. If you have four or more riders you can usually get an uplift for around $80 per person. And if you hate helicopters and want to ride up, well you can. Kirwans and the Croesus can both be ridden up comfortably.
With the Heaphy getting a shit-tonne of attention, the Old Ghost Rd about to open and tracks like Kirwans and the Croesus, it's solidifying the fact that the West Coast is pretty much the home of epic backcountry singletrack. Oh, and unlike the Heaphy, these other tracks are open to mountain bikers all year round!
The Westland MTB Club have this to say about the Croesus