The calculated distance (air line) between Pukchil-lodongjagu and Wŏnsan is approximately 116 miles respectively 186 kilometers.
By car or train, the actual journey to Wŏnsan is certainly longer, as only the direct route (as the crow flies) between Pukchil-lodongjagu and Wŏnsan has been calculated here.
Air line (approximately)
186 kilometers
100 nautical miles