The only official accommodation at Thong Pha Phum National Park are two rustic (electricity only from 6pm to 8.30pm) bungalows built on concrete 'trees' and a campground.The restaurant and snack shop don't keep regular hours, but there's always someone available around meal time if you inform them or the visitor centre.
All the other accommodation, including four 10m-tall 'Tarzan' treehouses ('Tarzan 1' is an actual treehouse, the others use a tree as one of four pillars) and regular bungalows down on solid ground, is slated for repairs (leaky roofs are one of the issues), but can be reserved directly through the park visitor centre. They all have mountain views.
Overnight visitors also need to pay the national park entrance fees.