The calculated distance (air line) between Yuen Long San Hui and Jardine's Lookout is approximately 15 miles respectively 25 kilometers.
By car or train, the actual journey to Jardine's Lookout is certainly longer, as only the direct route (as the crow flies) between Yuen Long San Hui and Jardine's Lookout has been calculated here.
Air line (approximately)
25 kilometers
13 nautical miles