Kaeng Krachan
run site at Villa la Flora, located in Petchburi province near Kaeng Krachan Dam. It takes around 2 and half hours drive from Bangkok.

Book you own accommodation
The hotel specifics are:
Rooms
It has 18 rooms (suitable for 2 people)
-10 rooms by the river with a weekend price of 2,200 baht including breakfast
-8 rooms in land on the other side with a weekend price of 1900 THB including breakfast
- Also, it has a room by the pool for 6 people all in one room for 5900 THB
- As well as a camp site, bring your own tent for 450 THB/person a night inclusive of shower and facility price. This includes breakfast.
Note that no pets in the rooms. Pets are allowed only in the camp site.
In total, this place could accommodate 25 rooms (and double that amount if people are sharing and +5 in the 6 room facility) and campers. Approx. 30 people.
Here is the Facebook Page of the hotel:
https://www.facebook.com/VILLA-La-FLORA-Kaeng-Krachan-2317858968296550/

In terms, of other hotel options near by have number in the proximity that are with in short driving distance of the hotel (5-10 minutes) a have linked a few near by if personal preference or budget does not match up to the hotel
Rim Keang resort         https://www.facebook.com/rimkaengresort
Bamboo resort       https://www.google.com/travel/hotels/s/1YCQhu1RaBNrNx1B7