Whether staying south in Sonoma town, which has a really lovely square, or north in Healdsburg, you will want to traverse Route 128 and enjoy the rolling hills of Alexander Valley, where so many fine Sonoma wineries are found. One huge difference from years ago is that many wineries only allow visits with appointments. Large wineries still permit drop-ins, but for trying many fine smaller ones, you must call ahead.
Some of my favorite Sonoma wineries include Vérité (meet Pierre, the winemaker; www.veritewines.com), Lancaster Estate (www.lancaster-estate.com), and Garden Creek Vineyard (a very small quality winery run by a Swedish couple, Karin and Justin; www.gardencreekvineyards.com). For just dropping in without an appointment, stop at Chalk Hill (www.chalkhill.com) or Robert Young (www.ryew.com). Note that many wine tastings have a fee and if you're making an appointment at a winery, there will be some pressure to purchase bottles at the end. I ended up buying 12 or so bottles from the three appointments. It does become hard to resist.
Most visitors to the region wish to explore not only Sonoma but Napa as well. Napa County includes the towns of St. Helena, Oakville, Yountville, and just plain Napa. Route 29 is the main road. Some of my favorite larger Napa wineries include Hess (www.hesscollection.com) and Domaine Chandon (www.chandon.com), no appointments needed. Do make reservations for the ultra fine wines of Opus One (www.opusonewinery.com) and Dominus (www.dominusestate.com). Finally Darioush (www.darioush.com) is worth a stop. The Romanesque columns in front are a bit out of Vegas (see above) but the wine is amazing. There's a tasting bar but, if you call in advance, you can get a private tour and tasting, plus a visit to the very pretty wine cave. Darioush is an interesting place not least because the owner Mr. Darioush Khaledi is an Iranian immigrant who built the winery from the ground up.
Final tip: If you want to splurge, arrange a car and driver to take you around to the wineries. After all, if you are sampling so much fine wine and cheese, you wont want to be holding back as the driver.
Next up, my top recommendations for hotels and restaurants in Napa Valley.