Clos Pegase is one of my favorite wineries to visit. The tours are fun and informative, and the winery includes a world-class art collection.
Others I enjoy are
Stags' Leap,
Ferrari-Carano (actually in Healdsburg),
Silver Oak (great Cabernet), and
ZD (excellent Chadonnay).
There are many other fine wineries (too many for one trip), so pick a handful and have fun. Since it is a few hour drive from where I live, I like to stay overnight at the unique Bed and Breakfast establishments.
Rubicon (formerly Niebaum-Coppola) is fun to visit because it includes a museum of props from Francis Ford Coppola movies.
If you enjoy cooking, the Culinary Institute of America is delicious.
Finally,
Opus One is outstanding, but rather pricey even for tasting.
As for dining, the Auberge du Soleil is less expensive for lunch and the view from the top of the hill is quite nice.
For fine dining in the evening, Cole's Chop House is great if you love steak, however, if you want some excellent choices from an eclectic menu, then I recommend Terra in St Helena (my favorite restaurant in the Napa Valley region).
Have a fun trip...
ADG