Concierge.com's insider take:
Less than a half-hour drive from downtown, Tijuana (abbreviated to TJ by locals), especially the area around Avenida Revolución, is dirty, loud, cheesy, and touristy to the extreme, but it can be entertaining. More upscale dining and nightlife can be found at Plaza Fiesta in the heart of TJ's Zona Rio (www.tijuanaonline.org). Giving Tijuana a run for its tourist money is the small, casual resort town of Rosarito, 17 miles farther south via the Rosarito–Tijuana toll road (www.rosarito.org). Slightly farther still is Puerto Nuevo, a tiny fishing village that's famous for its local lobsters served with beans, rice, and fresh tortillas. Driving across the border can be daunting, so take the San Diego Trolley to the border at TJ, then catch a shuttle from there straight to Rosarito Beach Hotel (www.mexicoach.com). If you do decide to drive, make sure you buy Mexican auto insurance, either from your rental car company or one of the many agencies near the border, before leaving the U.S.; then stick to the toll road and try not to do much driving after dark.