Thank you guys for the replies and sound advices . It's good to read that South Africa is also suitable for our venerable FT members. I feel relieved now
I've drawn a draft of itinerary like this:

D1: Arrival morning JNB – rest day/to be defined
D2: game drive excursion with guide at Pilanesberg Park
D3: Flight JNB – Port Elizabeth pick up rental car and drive to Tsitsikamma
D4 to D6 Garden Route: activities to be defined with the rental car (up to CPT)
D7: Transfer to Franschoek: Wine Tram in the afternoon
D8: Taxi to Stellenbosch for the Vine Hopper bus tour
D9 to D11: transfer to Cape Town: activities to be defined
D12: Flight Cape Hoedspruit or Nelspruit
D13: Visit the Panorama Route
D14: Flight to Hoedspruit or Nelspruit to JNB then flight in the evening to France.Given the time spent on the Garden Route, what are the essentials? Same for the Panorama Route?

Again the goal is certainly not to cram ALL those activities. She must enjoy at her own pace, so if some parts must be eliminated to provide her the best highlights of South Africa then be it.
I've never been to Blyde River Canyon, this is why this odd (=selfish) part was added, hope she may like it if it's worth the visit though (To Chetzel: which of those 15 attractions must not be missed?)!

Please amend/criticize/enhance the weird parts pls .