The calculated distance (air line) between Kaesŏng and Yangp'yŏng is approximately 61 miles respectively 98 kilometers.
By car or train, the actual journey to Yangp'yŏng is certainly longer, as only the direct route (as the crow flies) between Kaesŏng and Yangp'yŏng has been calculated here.
Air line (approximately)
98 kilometers
53 nautical miles