The climb to the final point of view takes about 2 hours and is quite physical but when the weather is clear, the reward at the top is breathtaking. You have a view over the bay and the plain below with its typical karst peaks. At the top, there is a small tongue of stone which has become the place to pose for THE photo that everyone made when coming here (the one I have put to illustrate Tab Kaek Hang Nak trail).Between the road to join the departure of the 3.7 km climb to reach the view, the ascent (2h), the time you will sepnd up there, the descent (1h) and the come back to Krabi or Ao Nang about forty kilometers away, count 6 hours for this visit.
This trail is very physical so avoid it if you are not in good condition and avoid it with very young children. Especially givent that there is no protective barrier and at the top we flirt with the void. An accident can happen fast. Take good shoes, a large part of the climb is on paths strewn with roots and stones. And bring a bottle of water. The rangers will ask you if you have one when you arrive and they won't let you go up without it (I imagine they sell some otherwise).