The actual 'Beautiful Rock Garden', which lent its name to the greater region, is a strange patch of eroded rocks known to Thais as Kunming Mueang Thai, 'Thailand’s Kunming', due to a slight resemblance with the Stone Forest in Kunming, China. Most visitors just take a tractor ride (starting at the visitors centre) up to the easy-to-reach viewpoint for a quick look, but the real highlight is a guided walk through the labyrinthine paths in the heart of the forest.
At times the hour-long route is a little rough and you need to duck through some small passageways, but it's not difficult overall and the effort is worth it. Some of the guides can speak a little English.