Transfers from hotel or just airport?

We won a Princess cruise and are leaving out of San Juan 2/20/05. We plan to fly in on 2/18/05 and see the sights. We have transfers included--but I understand we would have to return to the airport on 2/20 to take advantage of them? Will a taxi from the hotel to the pier be expensive--should we try to go back to the airport and take advantage of the transfer? Call us clueless-first cruise (but not the last).