The calculated distance (air line) between Chanthaburi and Krathum Baen is approximately 144 miles respectively 231 kilometers.
By car or train, the actual journey to Krathum Baen is certainly longer, as only the direct route (as the crow flies) between Chanthaburi and Krathum Baen has been calculated here.
Air line (approximately)
231 kilometers
125 nautical miles