Ride south from Cape Town on the coastal M6 (no, it is not a
motorway...! :o)
Then on to Chapmans Peak Drive (still M6). (This sections was
only re-opened very recently (2003, I believe). Was closed for
some years due to construction work after some quite bad landslides).
Its a great piece of road - especially the fantastic Chapmans
Peak Drive section - and theres not a lot of trafic.
The scenery is tops, the asphalt is super and the roads are
winding and hilly.
The weather was brilliant when I was there end November 2004
(blue skies and ~ 25 degrees...!).
Recommendation: Rent a large trailie so that you can go down
one of the many gravel or dirt roads to the beaches if you like.