In view of your concerns about driving, I would consider an organised tour.

Last year (and in 2009 when I previously visited) I used Easy Rider Wine Tours (https://winetour.co.za) who I'd highly recommend:

- very knowledgeable, personable guide (you essentially get the guy who owns the company, and he'll happily spend time giving you personal recommendations - if you remotely like port, go for the one he suggests from Simonsig which is superb for what is a relatively high volume producer),
- small group tours in a minibus
- good selection of wineries
- decent lunch with alcohol

They're probably also a bit cheaper than the norm, so in my case I didn't find anything not to like!