Here are the tracks.
Rock to Tswaing was a mix of dirt and tar. This will take you in via the 'back door' which is perhaps not such a good idea - we went to the picnic area then to the reception where we bought permits and then back to picnic area before going to the crater. (zoom in on the LOG to see)
Tswaing back to Pretoria was a horrible tar road - will have to find a better route back next time round.