4 continents - N America, SW Pacific, Africa, Europe.

There are BA flights from JNB to VFA; drive or fly outside the RTW from JNB to Kruger/Swaziland.

Although your profile says AA EXP, if you're not tied to oneworld, you might look at the Star Alliance 29,000 mile RTW - might need some fiddling with your itin but if originating in the US you might save $800 or so per ticket.

The OWE would be much cheaper if you could originate in E. Europe or Cairo and do the trip starting there, maybe in reverse.