Henry, I suggest you get the Nikkor 200-400VR plus TC(s).
I think this combo will provide excellent results. Focal length is very much needed.
If travelling in gameparks with a safari vehicle there will not be enough room for a tripod. A monopod, however, would be usefull as you could tie it to the hand bars of the vehicle.
For regular vehicle safaris a car window tripod + ballhead attachment such as that Kirk produces can be very useful.
Just a thought!
Enjoy your trip. Africa is a fascinating continent!
Cheers - Herman
PS. Oops I note the OP posted his message 6 years ago! Anyways its always good advise for future interested parties...