Located in Chiang Mai Province, Doi Inthanon National Park encompasses the highest mountain In Thailand, Doi Inthanon, as well as several lesser summits. The doi (mountain) is largely a granite batholith intruding a southerly extension of the Shan Hills range and forming the divide between the Nam Mae Ping river to the east and the Nam Mae Chaem river to the west. Lower elevations in the most easterly pant of the park are limestone formations and contain a number of caves.
Khao Sok National Park in south Thailand (near Phuket, Krabi, Khao Lak) boasts a spectacular landscape of limestone rock formations and ancient rainforest and can be best explored by boat or kayak or on foot (jungle treks). You can stay in tree houses and floating huts on a lake, or try glamping in luxury safari tents at Elephant Hills camp. (Black Dots White Spots travel blog)