AS an alternative, drive along the Newnes Road, leave your car at a marked carpark then wade across the Wolgan River and climb the hill up to the old rail embankment. There are signs and a seat here. Turn right and go along the old embankment on a slight ongoing ascent. This track is good although there were several washaways from a recent flood in late March 2021. Enter the tunnel valley picking your way up (often through) the creek. Enter the tunnel (it is curved so there is no daylight visible in the middle) then upon exit take the left turn towards the Old Coach Road and descend this almost 2WD standard road back to the rail embankment seat and descent to your car.
Best NOT to do these walks at weekends nor school holidays if you can avoid it. It can be very busy indeed there in peak times.