The calculated distance (air line) between Katwijk aan den Rijn and Zwolle is approximately 74 miles respectively 119 kilometers.
By car or train, the actual journey to Zwolle is certainly longer, as only the direct route (as the crow flies) between Katwijk aan den Rijn and Zwolle has been calculated here.
Air line (approximately)
119 kilometers
64 nautical miles