I was in San Salvador for 5 nights; partly a familiar affair and partly vacation. This was my second visit (first one was for 2 days about 3 years ago)
We stayed in San Salvador at the Hilton hotel Princess. You can see my excellent review on flyertalk and tripadvisor.
I would be very careful with driving anywhere. Signage is actually not bad but roads are bad and services very poor. Lots of dangerous areas in San Salvador and would NOT drive at night without somebody who really knows the area.
La libertad is nice; on the coast, nice restaurants. Just reviewed Beto's on tripadvisor. I really enjoyed a side trip on the road of the flowers (not too many flowers though) but the views are great. Plan a stop in the small town of Ataco.
By the way, I used the services of Mr. Francisco Rivas; he has a van for 12 people and an SUV for 4 people. Prices were very reasonable and he drives really well, speaks some English and is very polite, helpful and protective. I would be very careful with hiring a car/taxi without knowing who you are driving off with. The hotel can help you get somebody reliable.
Mr. Rivas' email is:
[email protected] and his phone is: 011-503-7703-3278. I have NO financial interest in his business but I AM a very satisfied customer. He also picks up and brings back to the airport at a great price.