About Springbok and the region
Springbok is the hub of activities before one enters Namibia on the Northern side (about 100 km from Vioolsdrift, the Namibian border). It is also about 100 km from the sea when driving West. But like most would do, Google can be your friend and feel free to ask in advance or when at Nasafi.
When traveling from Gauteng, Kuruman is 6 hours from Gauteng and 6 hours drive from Springbok. A sleep over might give you opportunity to visit places like the Augrabies falls.