I used to rent a villa with friends in Playa El Zonte in El Salvador. The beaches were pristine. The town was quiet at night. Very chill surfer camp vibe. Very cheap. Never felt really unsafe but driving in El Salvador can be tricky and scary. El Zonte is about an hour from the airport. Some hotels and VRBO's offer ride service. Its not for everyone, and the surf is strong. But I enjoyed it. VRBO might have some nice rentals too. 2 non stops a day from SFO. 5 hour flights.