Jeff Kingston > Bushwalking
The walks in the Glenbrook area don't connect up well. It might be best to take a car and drive from walk to walk, but if you don't have that option, and you walk in from Glenbrook Station, then you might want to walk out a different way, especially if you go to Railway Tunnel Lookout and Portal Lookout (both great).
One different way out is to walk from Portal Lookout to Lapstone Station. But despite what it says on the 1:25000 map, there is no track. You can follow the route marked on the map, however. Here is my guide to this route. I walked it in July 2012. It took me an hour and a quarter.
At Portal Lookout, pass through the `Abseilers Only' gate and look for a steel handrail below the cliff line, just a few metres from the gate. There are no steps, just the handrail going down rocks. Descend the handrail, descend the steel ladder below that, and keep going straight down. If you don't like the handrail or the ladder, turn back, because there is one more nasty thing, and it is worse than them: a 5m drop at the bottom of the cliff line which you descend partly with the aid of a rope, and partly on a fallen log. I'm no climber and I did it, but it's not fun.
After reaching the bottom of the cliff line, head straight down the hill towards the junction of Glenbrook Creek and the Nepean River. At first it is very scrubby but there is a faint track. Lower down it opens out and I lost the track completely. It wouldn't have mattered except that below that is a belt of lantana, not very thick thankfully. I scouted along the top of it until I found a good route down through it. This route was about 50m up Glenbrook Creek from the junction. It had lantana overhead and a rock face on the right.
Get down through the lantana and you are at river level. You now need to cross to the northern side of Glenbrook Creek, either by wading (knee-deep when I was there) or by scouting upstream for a suitable crossing. At the crossing I used, some of the boulders were uncomfortably round and slippery. Wading would have been safer, but I crept from rock to rock and got over. There might well be an easy crossing further upstream, I don't know.
After crossing to the northern side of Glenbrook Creek, walk downstream over boulders to the junction with the Nepean River. Turn left there and follow the Nepean. For the first five minutes there are rock shelves to walk along, then you see a faint track angling up a few metres over natural rock steps (not the earlier earthen track going steeply directly uphill, that just goes up and up as far as I could see). Beyond the rock steps, hidden from view until you get there, is a very uneven but perfectly clear track, still along the Nepean. Follow this for about twenty minutes until it emerges onto a real track at a T junction. Your trials are now over. To the right you can see civilization: the end of a sealed road. But your way is to the left, up the hill. At the electricity tower, turn right onto the rocky foot track going straight up the ridge. You could stay on the main track, but the foot track is a bit faster, and perfectly good. This brings you to within sight of Lapstone Station, at another T junction. Turn right there and you will come to the station entrance in a minute.
This route is very rough. It offers a variety of torments: a nasty descent through a cliff line, lantana, and a slippery creek crossing, and even when there is a track it is horrible. You might do better to slog back to Glenbrook.