We always stay in St. Helena and do small-production places, but I can help a little:
1. I would stay in/near the town on Napa (some nice hotels there) which would make the drive to Sonoma easy.
2. Keeping you relatively close to the Napa area so you don't have to drive too far: Wineries -- can't help on Sonoma. For a great view, maybe Chappellet on Pritchard Hill (20-30 min drive but will give you a great view of the valley). Decent wine and great view. Maybe hit Domaine Carneros for champagne. For a smaller production place, the new Krupp facility (very close to Napa) has a good view and great wine, and nice people.
Plenty of other stuff around (and also great stuff further up the valley, but trying to keep you from having to drive too far).
I would limit to 2-3 per day (we generally do 2), and actually enjoy the experience instead of seeing how many you can hit.
3. If you follow (2), you should not have consumed too much wine and can drive yourself. If you are going to drink a lot, Uber is there