To visit Khao Chang Phuak, visitors need to go to Thong Pha Phum National Park to make a contact with the officer. In this case, visitors should take a Bus from Mochit 2, Bangkok, depart from 5 AM, because after get off the bus at Thong Pha Phum district, visitors have to take a yellow Baht Bus (Songthaew) at Thong Pha Phum market on 10.30 AM (not sure for the other time available). It will take about 2 hours to the national park. By the way, to visit Thong Pha Phum National park with package tour may be available