From Pattaya, we will have to go back to Bangkok in order to take a plane for Surat Thani, which would be one of the easiest and quickest solution.
The tickets are less than 50 euros and will make me save a lot of time as bus and trains take a lot of time to reach this place.
Then, once arrived in Surat Thani, it only takes 1 hour transfer to arrive to the Khao Sok National Park.
The entrance fee for non local people is 300 Bahts as usual.
Everything looks amazing there. It is good to walk around in the jungle and do an elephant ride. It allows to go up and get some nice views.
It is also possible to take a canoe and do an excursion in the lake to see all the wildlife such as snakes, monkeys, wild elephants and so on. Check this out to give you an idea:
Many people do this trip with the agency Eco Voyages where there is a french guide called Sylvain who is very helpful. Then it might be worth to do this experience with him if it is not too expensive.
I will stay at least 2 days and a night because there is a lot to see there. Also, how cool it would be to sleep in these bungalows in front of the lake ?