There always seems to be travel involved when one wants to go rafting, so let's cover off how long it will take to get to the base camp, and what the options are.
Traveling by vehicle
Cape Town to the base camp
It will take around 9 hours to travel by car from Cape Town to the base camp via the N1 and N12. If you are able to stay over, then Beaufort West would be a great option. It is best to stick to the main routes.
Johannesburg to the base camp
This will take around 7 hours via the N1. From Kimberley, you can travel via Hopetown or Douglas to get to the base camp.
Durban to the base camp
The quickest route is via the N3, N5 and N8, via Bloemfontein and Kimberley, then via Hopetown or Douglas. This route is around 9 hours and 39 minutes.
Port Elizabeth to the base camp
This route will take around 7 hours and 39 minutes via the R75, R63 and N12. Please avoid traveling through Philipstown, Petrusville and Orania, as there are lots of dangerous potholes on that section.
Bloemfontein to the base camp
This section via the N8 and R357 will take around 3 hours and 15 minutes.
Pretoria to the base camp
This will take around 7 hours and 31 minutes on the N12, via Klerksdorp and Kimberley.
Traveling by Air
If you don't have much time to drive to the base camp, you can fly into Kimberley, the most convenient airport, and then hire a rental vehicle to travel to the base camp.
SA Airlink has many scheduled flights from most of the main cities to Kimberley, or Bloemfontein. You can rent a vehicle at the airport and then travel through to the base camp.
From Kimberley Airport to the base camp will take around 1 hour and 41 minutes, and it will take approximately 3 hours and 28 minutes from Bloemfontein Airport to the base camp.
I hope this was useful in indicating how much time you should allow for travel by road.