Caribe Hilton is quite nice, also, for an overnight. The rooms are roomy, clean, and the beach is not the best in the world but it's at beach! My room last year had a great view of the Condado and the ocean - very comfortable and as a female traveling alone I felt quite safe. There was also a great salsa band in the lobby during dinner hours, which really got me in the Caribbean spirit!
I paid $100.00 for one person but felt it was worth it. Have also heard great things about the Wyndham in Old San Juan which is closer to the ships.
Bon Voyage!