Yes, I did the explosives bunker, on a BMX (along with trying to stuff matches into it).Holy Crap! on a BMX! I built that few weeks before a whistler trip and never hit it up "just in case". By the time I got back a month and a half later I was more interested in the new trail some of the boys had built.
Kembla West is a great XC track (and it is legal).
I like to do the single track section at the north end on a hardtail as something different (V10 does seem excessive) agreed, but id parked at the top of the drift and it added more dirt time to my ride, though it is a shame that the shores fell into disrepair. Yeah, most were of a fairly dubiuos consctruction, soft timber.
Which Trig do you actually mean, the one on the southern end that is actually Kembla West through the bush (why would you ride a bike to here) Thats the one. there was a trail all the way out there many years ago, last time i went there it was "half a trail" but it was still worth the ride purely for the view