The Fodor "Essential South Africa" book does not contain much on many private game reserves. I am looking at recommendations for:
Port Elizabeth - Pumba or Sibuya
East London - Inkwenkwezi Safari
Richards Bay - Thula Thula or Hluhluwe-Imfolozi

Going to pick one or two of these (day trips) and trying to find recommendations.

The best private game reserves directly abut Kruger's fenceless border, such as Sabi Sand, Manyeleti and Timbavati etc. If you'd like a solid Big 5 experience, you should take a flight out of Cape Town to one of the reserve airports followed by a road transfer to one of many lodges at different budget points. You won't be disappointed! Leopard sightings are excellent!