The calculated distance (air line) between Kisra - Sume'a and Ashkelon is approximately 100 miles respectively 160 kilometers.
By car or train, the actual journey to Ashkelon is certainly longer, as only the direct route (as the crow flies) between Kisra - Sume'a and Ashkelon has been calculated here.
Air line (approximately)
160 kilometers
86 nautical miles