It takes a while to get there from Dumaguete (take the highway north up until Tanjay, then turn left towards Pamplona), but it's worth it.
After passing through Pamplona, going further west in direction of Bayawan, take a right at an intersection where they "forgot" to connect the side road to the one you are on. You'll know what I mean when you see it. One day I'll have to take a photo of that curiosity.
Concrete soon turns to gravel, and when I did that tour in August with my CRF 250 Rally there was plenty of mud and very deep ruts for kilometers in a row. That was a real piece of work. I actually ran out of water before reaching pavement again - bring plenty.
The well-paved road between Pamplona and Bayawan offers some nice twisties and very scenic views.