Welcome to FT.

It would be tight, but doable if you have a full day and make an early start. Pilanesberg National Park is a 2 hours drive from Sandton/Rosebank (where I normally stay), so you'd be spending 4+ hours on the road.

The earlier you leave, the better for a better chance of seeing wildlife, which become less visible during the day.

http://pilanesberggamereserve.com/index.html