Beautiful route into the mountains and then down to the coast of Koh Phangan. First section clockwise is on paved, steep road and then transitions into rugged dirt road terrain. The heat in May should be taken seriously as the route is very exposed and there is little water access the second half of the route. Heat is by far the most challenging aspect of this route so prepare accordingly! Spectacular views along the top with no road or foot traffic along seemingly deserted roads and trails the second half of the route. ~75% of the route is exposed to direct sunlight with ~25% shade provided by the jungle canopy speckled throughout the route. The jungle and scenery is absolutely stunning and we felt very safe along the way. Very easy to follow if you download the gpx file.
We should have started the route earlier as it was VERY hot (rookie mistake!). It was a bit of a slog up the paved ascent but we eventually found a nice pace. There was a local vendor on the side of the road which we bought a fanta soda from (delicious and refreshing)! Once we hit the dirt road there was a group of four wheelers (tourist) that passed us which we assumed they were making their way to the waterfall, which unfortunately our course route would not end up passing. In hindsight we should have taken a detour to see it! After a mile or so we essentially saw no one and the dirt road/trail become a bit overgrown but still very visible. The views along the way were stunning. During this more remote section Matt got overheated (did I mention it was VERY hot!) so we stopped at one of the only watering holes to cool off which was a relief! As we neared the end the route become less remote again and we met a kind local couple that offered us some cold water. What a treat! The end of the route revealed a beautiful beach which Matt jumped into immediately to cool off while I worked to find a way back to town. You can pay to take a water taxi (fun) or try your luck with hitching a ride with a local back to town which is what we did-- it was a bumpy, fun ride back! Such a friendly, welcoming country and island! To anyone planning to attempt this route I cannot emphasize enough that you should overprepare for the heat and bring more water than you think you may need! And bring 1,000 baht if you want to pay for a water taxi + additional baht to get you back to your hotel.