The only paved roads in the Kalahari region are:

From Maun to Gaborone via D’Kar, Ghanzi and Kang

From just south of Ghanzi to the Namibian border

from Kang to Hukuntsi

For everywhere else, and certainly for exploring parks and reserves, you’ll need your own 4WD unless you’re staying one of the region’s luxury lodges.