Leaving Cape Town spend a couple of nights in the winelands. Both Stellenbosch and Franschhoek are good stopovers. There are wine tours and great restaurants.
Carry on through the Robertson valley to join the R62 to Montagu, Barrydale, and Oudtshoorn. From there its across the Outeniqua pass to George and then Knysna, Plettenbery Bay and Tsitsikamma.
On the return leg take the N2 to Mossel Bay then through the farmlands in the Overberg region and Cape Agulhas at the southern most point of Africa. From there back to Hermanus for whale sighting during the Whale season from July to October. And along the coastal road back to Cape Town.