To get to Thong Pha Phum, take the main road 323 heading north out of Kanchanaburi, after around 130 kilometers you will arrive at Thong Pha Phum district. Turn left onto the 3272, you will then see a small town on the right where it is advisable to stock up on any food or other essentials needed for your trip, there are no 7 elevens inside the park. You will then pass Vajiralongkorn Dam (Khao Leam Dam) which is worth a look as it has great views of Khao Laem Reservoir. From here follow the 3272 which will gradually get more and more exiting and turn into a classic Thai mountain road offering great views along the way. The journey from Thong Pha Phum town could take 2 hours or more depending on how many times you stop to admire the views.