The calculated distance (air line) between Graaff-Reinet and Oudtshoorn is approximately 164 miles respectively 264 kilometers.
By car or train, the actual journey to Oudtshoorn is certainly longer, as only the direct route (as the crow flies) between Graaff-Reinet and Oudtshoorn has been calculated here.
Air line (approximately)
264 kilometers
143 nautical miles