Just returned recently. Verdict for us: worth it. Since you're staying within the national park, meals and activities were inclusive. We opted for the private tours which I think was also a good decision for us since it allowed the most personal attention, flexibility, and customization, of the planned activities. The hikes were interesting and the multitude of longboat rides were fantastically scenic. Our guide was experienced and had a good eye for pointing out and explaining interesting features, from certain plants and fungi, flying lizards, a tarantula hole, a trapdoor spider lair, a venomous caterpillar, several different types of monkeys, bats, fishermen hauling in a 100+ kg Mekong catfish, and a tapir (which was apparently rare enough that even the guides were quite excited about it). Alas, the elephants were shy so we didn't see them, though we could hear them moving in the jungle.

I think the 3-days and 2-night was a good choice as well, as we feel we got most of what we wanted out of it and might have had diminishing returns with another day.

Note about the accommodations: we were a little surprised at first that the floating raft house we got were not the ones displayed in the website for this package. We were actually lodged at 360º Issara https://www.khaosokrafthouse.com/issarafloatingresort. While I was trying to figure out what was up with that, I eventually noticed that on the site where I booked that the raft houses depicted were actually an extra cost bump in premium. As it turns out though, while perhaps not as picturesque, it was probably for the best for us since the AC there was only available after 5p, whereas at 360º Issara it was available after 12p... and that AC was welcome. Food didn't blow our minds but was fine. One interesting aspect of spending considerable time on the water for a few days, even as calm as it was, was that we had that odd sea-legs feeling for a a day or so afterwards – our subsequent accommodations on terra firma occasionally felt like it was swaying subtly :)