Adequate - 1 week:
To see Southern Africa in one week is not really advisable but is viable when only 1 or 2 "destinations" are selected and these regions are "travelled well”, e.g. include a few nights on safari, as well as a few nights in Cape Town and perhaps a night in the Winelands.

Very Good - 2 weeks:

A period of 14 days allows one to see quite a lot of the "better and more popular" destinations in SA, including Cape Town, the Winelands, the Garden Route and going on Safari, and/or a few nights in
Natal

Ideal - 3 weeks:

Three weeks is the ideal period required if one is to include most of the popular and best destinations not only in South Africa, but also have some time in Victoria Falls and Botswana.

Three weeks will allow a really "great itinerary" including many fabulous regions without having to rush from one place to the next, day after day. e.g. Cape Town, Winelands, Garden Route, West Coast, Natal, on Safari and even Vic Falls/Botswana, Kenya, Tanzania or Mauritius.

The recommended period of three weeks to travel here is obviously dependent on both budget and time available.