Sounds like a fun trip--hope you have a ball! There is a fairly recent thread
here on the Sonoma side of your question.
And a note with my recommendations both there and here is that I am rather lousy at describing my own palate preferences, so
caveat lector!
It depends on where you are staying, I guess, but I have always found the areas surrounding Healdsburg (eg Russian River Valley, Dry Creek Valley, Alexander Valley) to be very pleasant parts of Sonoma County to explore. It can be quite a drive to get over to the Napa side (depending what part of Sonoma you stay in), and alas, have had more difficulty finding stuff I enjoy on the Napa side (but there are others who are much better informed and hopefully they can chime in). Halfway up the valley, I think
Mumm Napa does a very admirable job (though many of their wines are widely distributed, my favorite--the
blanc de blancs was available only at the winery). Up around Calistoga I particularly enjoyed
Vincent Arroyo (the cabernet sauvignon and petit sirah 'port' still linger in my memory) [but one should note that I think Arroyo has achieved somewhat of a cult status, so you need to hit it the right time of year to actually be able to taste and purchase before it has sold out--I went in August which worked out perfectly].
And something to consider if you are interested in obtaining wines that are less available back home are the new multiple-winery tasting rooms that seem to be popping up all over Sonoma and Napa (though perhaps I did not notice them before). I had excellent experiences at both
Locals in Geyserville and
Family Wineries of Dry Creek Valley outside Healdsburg. It, of course, doesn't give you that "I've been there" experience, but, quite frankly I don't know where else I would have had the opportunity to buy, nevermind try
before I buy, a wonderful
Duxoup Charbono that I picked up at Family Wineries (I hadn't even heard of the grape, nevermind the winery!)
Linda Marquis wrote:fortunately there are 5 of us and we'll take turns being the designated driver
Bravo and thank you! Happy travels!