Valle de Guadalupe
They say "Good roads make for bad tourists, bad roads make for good tourists." The roads aren't great in Valle de Guadalupe, just south of the border ~2 hours from San Diego, but there are over 100 wineries, many great local restaurants and friendly people making surprisingly good wine. It's a rustic, Mexican version of Napa. Encuentro Guadalupe is probably the most unique hotel I've ever stayed in.