Upvote:5
From Bergville, you probably have to rely on the kindness of strangers, but from Johannesburg to Bergville should not be a problem.
One option is to take the Joburg to Durban train and get off in Ladysmith (at 2:45am). Another is to take the 8:15am Greyhound to Harrismith, which is scheduled to arrive at 11:25am. That should be early enough to get you to Bergville, but I don't know where the combis leave from in Harrismith.