Hi Toz,
I hope you have a great time in Adelaide! I have done a Trailhopper tour in McLaren Vale, and I know they run tours in the Barossa too. I really prefer it to a standard tour as you can pick and choose the wineries you go to and how long you spend there. There are others like Bums on seats, Gray line tours, Groovy grape. Here is a list you could look at:
https://www.tripadvisor.com.au/Attra...Australia.html
In terms of restaurants, Adelaide has a lot! There are some really nice ones in the Barossa, Adelaide Hills or McLaren Vale. Penfolds Winery has a restaurant in Magill (about 15 minutes from the city), but there is also Orana and Georges on Waymouth which are great too. There's also Hill of Grace at Adelaide Oval. While the food is very well done, the service was severely lacking, and I personally wouldn't hurry back.
When will you be there? If you're going to be there when it's warm, I highly recommend heading to the beaches. Glenelg is the easiest to get to, but locals are big fans of Henley.