I have to tell you, the wineries that are much closer, in the Gilroy, Watsonville and Morgan Hill area, are generally nowhere near as good as the ones I recommended, which are amongst the best of the Santa Cruz Mountain area.
FYI, Ridge is closer than you think - it's about 40 miles from San Martin, where Cordevalle is, and 30+ miles of that is straight shot highway driving. The others are probably 20-30 miles further.
Basically, take the CA-85 to Cupertino at Stevens Creek, and Ridge Winery is about 6 miles up Montebello Ridge Road from there.
Incidentally, distances between wineries in that area are typically much longer to drive than as the crow flies. For example, Ridge and Santa Cruz Mountain Vineyards are on adjacent mountain ridges, probably less than 5 miles apart as the crow flies, but it's probably 25-30 miles of driving between them.
A couple of wineries that are in the Saratoga / Los Gatos area that are good are Cinnabar and Testarossa.
In the opposite direction, heading south from San Martin, there are a handful of funky wineries about 10 miles south of Hollister along Cienega Road, including one genuinely great, important winery, Calera. This area is really off the beaten path, so it will be a very different experience than Napa or Sonoma. But well worth it, especially to visit Calera, and while you're there, the other few wineries right nearby. You probably should call these wineries before visiting, as most do not maintain tasting rooms in the sense of Napa or Sonoma - you will probably be tasting right in the barrel aging rooms at most or all of them.
http://www.cheers2wine.com/san-benit...-wineries.html