Not from South Africa, but I spent 2 weeks driving the length of the country.
I would highly recommend a detour off the garden route into the Karoo, just take a left at Port Elizabeth. Lots of ostrich farms in the Karoo (in and around Oudtshoorn). It looks something like this -
Penguins at Boulder Bay, large honking birds (I'm not a birder) at Kruger National Park up north. All round great country to have a camera around your neck. I wish I was as into photography back then.
If you plan on driving, remember to stop well before a traffic light (they call them "robots") at junctions. Gives you some room to maneuver in case someone walks up to your window (my local guide and bestie was a cop, and she was all about defensive driving techniques). It's a bit unsafe, especially in and around the cities.
Not South African, but lived there, in the Cape, for a decade. I worked in tourism and know the Garden Route very well professionally and personally. I'm away for a few days but when I get back ill be in touch and maybe I can help.