Randy, unless you have a guide/friend in the Barossa or Clare Valley, consider engaging John Baldwin to drive you. My wife Janet and I took two tours with John and had a delightful and educational time. John seems to know everyone in the wine areas around Adelaide; we spent three fascinating days together.
One of the highlights was John arranging for me to become a member of a wine tasting group that, by chance, had a major tasting of over 30 Sparkling Shirazes (aka Sparkling Burgundies), with at least 60 members present and very welcoming to this Yank.
John's cars are immaculate, his food is delicious, the wine and winemaking introductions are priceless.
Libby, his wife, makes the arrangements, and she is as delightful and John himself. One of the great advantages is that you will travel with John himself -- no one else drives his cars. We learned that other highly rated tours are sometimes led by the big gun, but often led by assistants of lesser caliber. John was the first in the Barossa and by many accounts still the best.
Very highly recommended.
http://www.barossadaimlertours.com.au