Riding in Jozi compared to Cape Town is a tough adjustment - dont underestimate altitude training! Cradle is the best bet and get involved with either Cycle Lab in Fourways or Club100. The morning ride from Engen on Main Road is a good training base and there are always people on the route if you lose the group. I would suggest getting a mtb though - its much easier to train than on the road.
That was some of the best scenery in the country, fantastic single track but i must say the last 20kms was a severe test of character and endurance...do not enter into this race if not 100% prepared!
