This is a top walk and highly recommended.
I found the start of the track using Tas Trekker's notes, but it's one you could easily miss if you're not looking carefully. The photo shows the cairn.

- Start of track
When I was there in Dec 09, there was a parking space on the side of the road finished in grey gravel contrasting to the surrounding brown dirt. Bracken ferns were starting to overgrow much of the logging area, although staying on the snig tracks was not difficult (it was very steep initially though!). The tricky bit is identifying where the track leaves the logging area and enters the old growth. A bit of patience is about all I can suggest.
The track is well cairned once you find it, although not obvious to follow due to lack of traffic.
After a while in the forest, you exit onto standard dolerite scree. Its about an hour's worth and not overly well cairned. There's a pole with pink flagging marking the point where the track descends into the bush, which could be quite handy.
There's a few tricky spots to get off the scree onto the plateau, but again nothing a bit of patience won't solve. From there, you can make your own way to the summit across alpine heath (eg scoparia) but generally good going and no scrub bashing required. There's a very substantial cairn (2m tall or so) about 5 minutes walk south of where you hit the plateau, which would make a good marker on the way down.
The view from the top toward the Walls is just excellent. I headed to the eastern edge of the summit block and enjoyed a long lunch in beautiful weather. It would be a dangerous spot if you got clouded in though. There's no track on top, and minimal landmarks. All up, I took 6 hours walking time. Distance is around 8 - 10km, with around 700m of elevation gain.
Again, this is a top walk, very isolated feeling.
Wello