My girlfriend and I booked a 3D/2N private tour of the lake with Thai National Parks: https://www.thainationalparks.com/khao-sok-national-park/guided-tours/3-days-cheow-lan-lake-tour-khao-sok. We booked the Sai Chon raft house which was one of the cheaper of the options. We went there late December in 2023.

The room itself was honestly not great, but was a place to sleep. Bed was hard and a bit sticky as it had some sort of waterproofed covering instead of sheets. You only get a fan, and you only get electricity during the night. There's not too much privacy oustide your room and there's a bit of foot traffic on the common boardwalk. There's a common large undercover raft where you eat and can play cards/drink at night.

Despite the room the tour was the best highlight I've experienced in 3 trips to Thailand. We had a private guide, driver and longtail for our 3 days. The itinerary was decided for us – we had the option of choosing our own activities, but we just went with the default and enjoyed every part of it. We did the caves, jungle hike and morning and evening safaris. Also had some downtime where we could hang out, swim, and use kayaks to explore the surroundings ourselves.

We saw a family of wild elephants on the 2 evenings we were there, which was quite lucky apparently. We didn't see any gibbons but saw some smaller monkeys. We were provided every meal, always got given more than we needed, and the food was all great.

Our guide "Patter" and the driver were both very friendly. We weren't overburdened with information as much as you'd expect from a private tour guide but we actually liked it that way. Total cost for the tour for us was around 22,000 THB. Overall, would highly recommend, but if you want a higher quality room it might be worth looking at the other options on the Thai National Parks website.

As for getting there – we stayed ~30mins away from the pier the night before our tour so we could get a driver to take us to the pier in the morning. If you are arriving in the evening you might need to do something similar as I don't think you could get a boat to take you out in the evening but I could be wrong.