I recommend that when you go to the wine country, you pick no more than 5 wineries to visit in one day. Pace yourself. If you visit 5 wineries, spread those visits over a 4 hours period.
Also pack lunch and bring water. Plan your trip so you get to the first winery at around 11 am or so. That way you won't be rushed, you can linger over lunch, and you can see a good cross section of our terrific wineries!
The Sonoma wineries typically will let you taste about 5 (and sometimes more) wines - starting with a Sauvignon Blanc, then Chardonnay, then Pinot Noir, then Zinfandel, then Cabernet Sauvignon. Sometimes the tasting will end with a dessert wine. Added altogether, these individual tastes can equal a full glass of wine or more. Therefore, if you hit 3 wineries in relatively close succession, you could suddenly find yourself over the legal limit for alcohol consumption. It's always wise to have a teetolar in the group who can be your designated driver.
We are no strangers to 'Bush'fires in Australia and we followed the news of one in the Healdsburg area during our stay. We wouldn't have gone anywhere near it had there been any danger-no place for tourists but we were perfectly safe especially since the firefighters seemed to be staying at our motel! We counted 30 plus trucks.