If you want to trip to Phetchabun from Pattaya by bus, you can use bus operators which have route to Phetchabun from Pattaya are as folloiwngs;
Phetprasert : The bus terminal is located at Sukhumvit Road, between intersection of Pattaya North Road and Pattaya Klang (Central) Road, just close to entrance of Motorway No.7.
>> Go to Phetprasert