The calculated distance (air line) between Yuen Long Kau Hui and Kai Tak is approximately 14 miles respectively 22 kilometers.
By car or train, the actual journey to Kai Tak is certainly longer, as only the direct route (as the crow flies) between Yuen Long Kau Hui and Kai Tak has been calculated here.
Air line (approximately)
22 kilometers
12 nautical miles