Khao Yai is accessible by two different routes from Bangkok, but the Saraburi-Pakchong route (Highway 2) is the most popular because it passes through a number of tourist attractions along the way. The Prachinburi route runs through Wang Nam Kheo and its steep slopes with sharp turns. No matter which route you take, these two merge at Khao Yai National Park’s headquarters.
Although you can take a bus from Bangkok’s Northern Bus Terminal to Pak Chong, then transfer to a song taew (passenger-carrying diesel truck) to the park’s headquarters, it is not recommended because you will not be able to hitch a ride to visit various attractions once there. It’s better to rent a car or hire a van with driver, to experience all that Khao Yai has to offer.