How about Underberg KZN. Gautengers and Freestaters can come via Lesotho and Sani pass, Eastern and Western
Cape people via Wild Coast, limpopo boys via, I dunno, Swaziland and or isiMangaliso Wetland Park. (St Lucia).
A good central point may be Colesberg, seems to be about 700km from Jhb, Cape Town, Port Elizabeth.
My 2 cents worth.