Why not take the last flight the night before from CPT-JNB and spend the night at the Intercontinental at JNB? You won't miss a thing in Cape Town on that last day except you won't have a room after the 11am check-out on Saturday morning. If you take the 545am flight you will need to wake-up at 3am. That does not sound like fun. Since there is not huge traffic on Sunday morning you could fly Saturday afternoon and spend Saturday night at Fairlawns or Saxon in Jo'burg if you wanted with an early transfer on Sunday to JNB arriving around 730am.

Craig Beal - owner - Travel Beyond