Last year in May, dudes (Mike and Lev) took me to Lodi ZinFest, an annual Zinfandel festival. It was a very nice and relaxing day trip during which I had much too much wine :)
If I remember correctly during that day we visited 4 or 5 wineries (the ones that I remember and would recommend you to visit were: Michael-David Winery, Jessie's Grove Winery, M2 Wines). Each of these wineries was completely different in style: some were bigger than others, some were more commercial and some had more home touch to them. Still, at each of them there were not that many tourists and (as a result of that I guess) at almost each of them we had a chance to talk with the owners and get a lot of information about wine making process.
Here are few pics.
Mike and Lev at Jessie's Grove winery:
One of the wines that we tasted:
Intro to wine making:
Wine fermentors and storage barrels:
Mike and I at Lodi Lake: