We just got back from the AOS cruise out of San Juan. You are going to LOVE IT!!
We arrived in SJ on Saturday, toured Old San Juan Sat. afternoon and evening, and walked the beach/swam Sunday morning. We got on the ship Sunday around 1:30 pm. It took us fewer than 15 minutes to hand in our luggage, get our SeaPass card, and get on board.
They tell you that you can get off again as long as you are back on board by a certain time. I forget what time it is as we didn't leave, but you have to be there for the muster drill. The terminal is not really close enough to walk anywhere, although it is a short cab ride to Old San Juan.
My suggestion would be to see what you want to see on Saturday. I think they allow you to start boarding at noon or 1:00 pm, and they have a lunch buffet available in the Windjammer Cafe as soon as you board. You can visit your stateroom after 2:00 pm. All of the pools are open, and there are a lot of things on board to see and do. . . .You know they have a fitness center, rock climbing wall (It was not open Sun. afternoon.), miniature golf, rollerblade center, etc. And, you can view excursion videos and such in your room.
We found the crew absolutely wonderful. We did not like the fact that they charged extra for soda or juice($1.50 per drink or $42 per week per adult) and that they didn't have irons or laundry facilities. Other than that, we had a great week. Make sure you see the ice show. It really is good!!
I hope this helps!!
Read and post cruise reviews
Veracruz - '85
CCL Tropicale - '94
RCCL Adventure of the Seas - '05
CCL Valor - '06
CCL Victory - '06
Celebrity Century - '07
CCL Triumph - '07
CCL Victory - '08
NCL Gem - '10