This is the short walk option to get to the cave, driving there is a bit longer though so if you would like more walking time and more elevation gain, try the long Ritcher's Cave Walk. This is really best for 4wds so you might consider the longer walk or there is a carpark 2km before the start of this walk with a parking area where you can start from instead (track shown in yellow below).
This has plenty of lovely rainforest and elevation gain so its great for getting fit. Finding the caves themselves can be a bit challenging so we advise if you are going to find the caves let someone know where you are going and when you are expected back. Allow a full day for this walk.
It is a lot of fun scrambling over the rocks at the base of the cliff, be very careful of your footing as this is not a well travelled walk and there are large sections of honeycombed rock that have fallen and may be thinner than you think. It is not so much a walk as a bushbash.
Start at Red Hill Road that continues on from Forest Road, google may try to take you in from the south, change it to the "longer option" from the north that comes off Bumble Hill Road to minimise the your 4wd driving: -33.267469898574355, 151.33615493774414 Google Maps Link
You have arrived at the campsite, head to the back of the campsite to the east until you see the path, slightly south east: -33.27565, 151.3145 Google Maps Link
Continue along the track until you get to a large rock platform, the path down to the caves is just before this in the empty riverbed/ ravine, that looks too steep to be a path, some bum shuffling is called for. Once down continue along the cliff line, just below the 250m contour, there is a bit of climbing involved occasionally: -33.27565, 151.3145 Google Maps Link
Head back up another ravine after the caves end to the road: -33.27629, 151.31168 Google Maps Link
Turn left onto the road and head back to the start: -33.27579, 151.31147 Google Maps Link
This is the campsite - the path is behind and slightly to the right of here.
Path behind campsite
Path down the ravine
If you reach this rock platform you have gone a bit to far, the path down if is the very steep ravine just before this.
This is part of the very steep path down.
This is the path back up at the end after the caves