Drive-able from San Diego and has a wine country region? Enter Baja California, which is quickly becoming a popular destination for beach, food, and surf lovers on a budget. Inexpensive lodging and eats are readily available, as are the nightlife parties in town. Hit up Tacos El Yaqui for some good Mexican grub or head to Popotla, a fishing village with a market that serves seafood straight off the boat. Both will feed you for cheap, and you can slug a well-made margarita pretty much anywhere. If you're in the mood for a bit of shopping, stroll the main street or head to the town's mercado (market).
Note: Make sure you have the proper insurance for crossing with your vehicle into Mexico. Hiring a driver to visit the wineries from southern California is a possibility as well.