In Kalahari desert there is the Kgalagadi Transfrontier Park partly in South Africa (approx one third) and in Botswana (two thirds). The South African part is called Kalahari Gemsbok National Park and Gemsbok National Park in Botswana.
We recommend Twee Rivieren and Nossob kemp, both close to Botswana border. The third camp, Mata Mata, is close to Namibian border. We recommend to stay at least 3-4 nights.