We docked in San Juan around 5am. Passengers (via express disembarkation) began leaving at 7:00. We would have opted for this and an earlier flight home. However, when we booked our plane tickets there was some confusion about whether or not this option was available on Princess in San Juan. So, we opted for the later flight.
Having spent a fair amount of time in Old San Juan, we opted for a shore excursion / airport transfer ($39/pp.) to visit El Yunque, the Caribbean National Forest. We departed the ship at 8:00am and were on our way to the rain forest about 30 minutes later. The drive takes 45-60 minutes (each way). We made a number of stops in the forest, including a 20-25 minute walk along a nature trail. Today officially starts the rainy season… a fact that wasn’t lost on us during the visit. 
Here’s a photo of one of the waterfalls in the park:
Like our other rain forest experiences, this too was lovely. Who knew? Puerto Rico is great!
We returned to the airport around 1:00. Since we have only carry on luggage and because I snagged an upgrade again for us on AirTran, we were able to skip the LONG check-in lines and the LONG security lines. All told, we managed to zip through in less than 15 minutes (versus what I have to imagine could have been a 1-2 hour process).
We’re now awaiting our flight which departs in a few hours.
Another successful trip! Six more countries (making the total 45)!
Next up (in July) will be our beloved London and then on to Northern Europe.
Sounds like you had a fun cruise. Welcome home.