The Kalahari is reasonable flat and a desert. The challenging bit is not hills but the sand ..... the whole area is covered in either a white or red sand ...thus Red or White Kalahari.
Walk and stalk is not very often used and lots of hunting of the back of vehicles which I believe, if you are to unfit, fat and out of shape to walk and stalk, hunting from a vehicle after chasing the animal down ... you are a coward and not a hunter!!
Looking at temps in the 110's in summer ...an amazing endurance challenge ..... couple that with lack of surface water and heat stroke is a real danger!!