Depends on your exact route and when the rainy season starts. Most roads in Botswana are flooded during the rainy season and a 4WD vehicle is required for the height (also be sure to get one with the air intake mounted above the fender, preferably at roof level). During those conditions a normal SUV is not adequate (unless you are willing to add a few weeks to the duration of your trip while you wait for the roads to clear up). Within SA the highways are fine (comparable to secondary roads in the US but with some freeway sections near main cities). The driving is challenging due to the presence of slow trucks doing 20 mph on the highway and erratic driving by others. Remember to drive on the left (you probably want an automatic as shifting with your left hand takes some practice while dealing with traffic). If driving in certain parts of Johannesburg remember than carjacking is a big problem and the law allows you to run red lights if your life is in danger. Some cars take undue advantage of that, so don't be surprised to see red lights being run at will. Crime in your route is not a problem but some parts of Kwazulu-Natal (SE part of SA) are to be avoided unless you have a local guide (a dozen body guards is useful too). Personally I would avoid any area that I had not researched ahead of time (for road and crime conditions). And if you haven't driven off-road before, rethink your trip or do it in convoy (at a minimum rent a satellite phone). Flying into VFA is an option, as is flying into WND.