The tour is amazing, I recommend taking it to everyone who visits Huahin.
We've agreed on our own itinerary beforehand with the managers of the tour, so the itinerary you can see here is just an option. The driver was very nice and helpful on all the parts of our journey, and though he didn't speak English well we had no problem communicating with the help of Google Translate on our phones.
We've visited the Phraya Nakhon cave first: took the boat halfway and then climbed the second mountain. The climbing part takes a lot of energy, so if you wish to save it the boat is a good option. It costs 400 baht (2-4 people) and takes you to the second mountain and back after you return from the cave. The second mountain is quite steep and I recommend finding some long sticks at the foot of the mount, it will make your climbing much easier. The sights on the way to the cave are very beautiful, so even if the climbing is hard, it is definitely worth it. The cave itself is magnificent and you have to get to the cave between 10 and 12 am to get the best view of the pavilion in the light beams.
After that we've visited another cave (unfortunately I don't remember the name of it), but we didn't go deep inside because the guide told us that it requires crouching and my mom's back prevents her from doing that. The nature is still amazing all around the Khao Sam Roi Yot national park, so even the driving around part of the journey is very exciting.
The last stop was the Thung Sam Roi Yot Wetland, the swamp-lake near the mountains, full of lotuses and lovely birds of all types. You can just walk around it on the wooden boardwalk or you can book another boat for 500 baht (2-4 people) and it will take you around the lake for about an hour and you will see the wildlife and some magical lake-mountain views. We've seen not only the birds but the whole monkey family on a tree:) The lotuses didn't bloom mostly, but it was still a breathtaking view.
As for the tickets, aside from the boats it costs 200 baht for a person to buy a ticket to the whole national park, and after that you just show the same ticket in all the places you visit.
We are also very grateful to our driver that he took us to a small fruit market on the way home upon our request.
All in all amazing tour, highly recommended.