*2015 update*
I've been here for two nights during the week at the end of November, and found it fantastic! Even though it's 40km from the nearest town (Mittagong), from which half is a dirt road through the mountains. Quite challenging, but amazing views. The owners are super friendly and will inform you about the conditions of the road. I did fine in a regular Toyota. Just slow your pace and pay extra attention to the narrow roads and you'll be good. From Sydney it's roughly 2-2.5 hours depending on traffic.
The actual nature retreat is HUGE! It's like the complete valley, and you're allowed to hike nude anywhere, camp near the river, etc. They also have cabins and caravans for hire. There are pools and spas and a small shop. I've seen kangaroos, turtles, wombats and various other wildlife, which was so cool. Owner Colin told me that you can get really close to the kangaroos when naked, while with clothes on they run away much sooner. Funny how nature works.
There also is a huge 4x4 area with a lot of tracks. Colin was so kind to take me on my first (nude!) AWD tour and showed me around. A-ma-zing! We travelled paths I considered impossible and drove back up to the mountains. The area is also used to let new owners get familiar with their 4x4 vehicles, which must be great fun for them. They do AWD tours in the weekends, and you can always ask on other days as I did.
No cellphone reach, nor wifi. Completely offline for a few days since ages and it felt good. :)
It was really strange to put my clothes back on at the day of departure. Owners Colin and Katina are not the youngest anymore, but they can be very proud of what they have achieved with their retreat. Started small and extending it bit by bit till what it is now. In my honest opinion one of the best places for nudists to be in the world.
I really hope to be able to travel to Australia again next year, and I'll return here for sure! Needless to say I'd highly recommend this place.
(the picture is me during a hike)