There are so many wineries and so little time as most are open between 10am and 4pm so you don't want to waste time waiting for food in a restaurant for lunch. Additionally almost every vineyard has gone through the trouble of making a beautiful picnic area, since they don't sell food they hope you'll bring your own and buy a bottle of their wine to go along with it (you can also avoid the restaurant mark up this way), and who has a more beautiful setting than around the vines.
Just off highway 154 is the Los Olivos Market, a fabulous country market where you can purchase picnic items and while they're making your sandwich or steak you can shop for local products including lavender soaps and lotions from a nearby farm. Out in front of the store they barbeque tri-tip (I guess a Califorina thing, try it if you’ve never heard of it), and they’ll package it up for you so you can take along a picnic for your drive through wine country. Some wineries sell small snacks but none of them offer a full meal so it’s up to you to stop at a restaurant or pack a picnic. If you don’t feel like eating bbq tri-tip the market has a full gourmet deli and cheese counter in the back of the store.
If you’re starving and can’t wait to drive to a picnic location, you can dine in front of the market on their picnic tables although I’d wait especially since Bridlewood is just across the highway. Bridlewood has a hidden picnic area out back that has some of the most beautiful scenery in the area. Horses graze next to a lake in front of a hill covered in grape vines. Then there is always Beckman which is just a few more minutes away and has the best wine in Santa Barbara along with gazebos for picnicking built next to a small pond. Firestone which has a fabulous wine tour (only 1 of 2 that we know of) and a beautiful picnic area. Gainey and Rusack also have great areas to picnic, explore on your own and I'm sure you'll find many of your own favorites as well.