The calculated distance (air line) between Prachin Buri and Krathum Baen is approximately 79 miles respectively 128 kilometers.
By car or train, the actual journey to Krathum Baen is certainly longer, as only the direct route (as the crow flies) between Prachin Buri and Krathum Baen has been calculated here.
Air line (approximately)
128 kilometers
69 nautical miles