The calculated distance (air line) between Nakhon Ratchasima and Phitsanulok is approximately 177 miles respectively 285 kilometers.
By car or train, the actual journey to Phitsanulok is certainly longer, as only the direct route (as the crow flies) between Nakhon Ratchasima and Phitsanulok has been calculated here.
Air line (approximately)
285 kilometers
154 nautical miles