Continuing a bit up north, after the first waterfall, we can reach the most famous one which is the Sai Yok Yai.
Indeed it is famous because of the quality of the nature. We can find caves with bats inside.
The waterfall itself is also famous because the king Rama V used to come to swim there.
Also, it is good to mention that the entrance in each national park costs 200 Bahts.
I heard that near the river, there are some floating huts where we can sleep in some hammocks. However I checked the prices for the ones near the river Kwaï and it costs more than 100 euros for the night, which is far too expensive.
Worst case scenario I will still have my hammock with me and I can sleep in the jungle if I manage to get some food and water with me.