If you do use the lower track coming in from the south end means that you can mesure the distance from the intersection on your speedo and find the track. I think its about 1 km (check the guide book). The cairn and track are fairly easy to miss. When we were there a few months ago a group coming from the other direction missed the track. Because the fire has opened up the path its probably not worth being hassled by the rangers for the time you save on the waterworks track. Its also better if climbers dont piss of the rangers. If we are less visible and have less impact access is less likely to be a problem. Although in this case using the waterworks track would negate the need for the lower half of the track which would suit everyone. But this is parks victorias call.