It takes roughly one hour to hike from Hat Yuan to Hat Rin on a jungle trail or about little more than by boat if you include waiting time. Very steep uphill and downhill, high humidity, mosquitos, snakes, roots looking like snakes, spikey vegetation, monkeys and wild pigs. Love it. The trail itself is omewhat difficult to find and follow, unless you are familiar with it. It took me three times to get it right and I got somewhat lost in process too. Apart from being eaten by mosquitos for hesitating long enough I suffered no consequences. I heard a story about a guy who got spent five days in the jungle of Ko Phangan trying to find his way to civilization, which sounds a bit mind-blowing considering the small size of the island. Being used to the safety of the Finnish forest (apart from ticks, which are complete assholes), I do not know how dangerous Thai jungle can be. Yes, there are deadly snakes and dengue fever carrying mosquitoes, but whether there are high chances running into those provided common sense is something I have no idea about. Proper shoes and long pants is a good idea, though.