Stuart,
There are basically 2 mapsets (which will work on Garmin units) for CT.
Tracks for Africa (t4a):
designed mainly for off road driving but also have most of the major roads in and around the cities
not routable
Best if you are going on safari or visiting national parks or game farm type places.
Cheap +-R600
Garmap Streetmaps version1 (sv1):
the SA equivalent of the Garmin City Navigator products.
routable
can only be loaded on one GPS (so you can't copy from a mate in SA
)
expensive: R2500
If you were travelling here regularly, i'd say go get the sv1, but if it's just for a holiday then it's hardly worth it. IIRC, the car hire companies do also hire out GPS's with sv1 loaded. I will be going to the airport next week, so will have a look around and see who is offering what if you like.
When do you get here and for how long?
Regards,
Dale