This was the best experience in Phuket. We had just been to a shop with a small spider monkey and I was appalled that they were proud to have it in a small cage. The driver saw I was upset and told us about the GRP which was not far away. We visited with 7 other Australian and we were amazed at the work that these volunteers do. It was a real eye opener. Please give some money while there as they do not receive any money from the park admission fee. With regards to the waterfall you need to be nimble and sure on your feet. Put the GRP on your list of must do's in Phuket.