The calculated distance (air line) between Nakhon Ratchasima and Krathum Baen is approximately 153 miles respectively 247 kilometers.
By car or train, the actual journey to Krathum Baen is certainly longer, as only the direct route (as the crow flies) between Nakhon Ratchasima and Krathum Baen has been calculated here.
Air line (approximately)
247 kilometers
133 nautical miles