The calculated distance (air line) between Mennzel Bou Zelfa and El Kef is approximately 110 miles respectively 177 kilometers.
By car or train, the actual journey to El Kef is certainly longer, as only the direct route (as the crow flies) between Mennzel Bou Zelfa and El Kef has been calculated here.
Air line (approximately)
177 kilometers
96 nautical miles