The calculated distance (air line) between Wichian Buri and Krathum Baen is approximately 150 miles respectively 241 kilometers.
By car or train, the actual journey to Krathum Baen is certainly longer, as only the direct route (as the crow flies) between Wichian Buri and Krathum Baen has been calculated here.
Air line (approximately)
241 kilometers
130 nautical miles