The calculated distance (air line) between Krasnogvardeyskoye and Mykolayiv is approximately 150 miles respectively 242 kilometers.
By car or train, the actual journey to Mykolayiv is certainly longer, as only the direct route (as the crow flies) between Krasnogvardeyskoye and Mykolayiv has been calculated here.
Air line (approximately)
242 kilometers
130 nautical miles