The calculated distance (air line) between Ryūgasaki and Yōkaichiba is approximately 25 miles respectively 40 kilometers.
By car or train, the actual journey to Yōkaichiba is certainly longer, as only the direct route (as the crow flies) between Ryūgasaki and Yōkaichiba has been calculated here.
Air line (approximately)
40 kilometers
22 nautical miles