Cabo was pretty boring as it was cut short by several hours due to our late embarkation. All excursions were cancelled, it was Christmas Eve, it was too early in the year for whale watching, and we only had a 2-3 hours there. We just walked around. IMHO, there is not much there anyway except Americans, golf and tacky tourist shops. Scuba Diving would be great but was not an option due to cancellations. It has pretty beaches, and it is fun to see El Arco, (the arched rock formations) but it is so Americanized, with endless condos and high rise hotels and golf courses. Didn't feel very exotic or that there was much to see.
The nice thing about Acapulco is that the port is across the street from the old fort/museum so you can at least do that on your own. The port is in the city as well, so there are many ways to navigate for your day. We booked with Rudy's Tours online and he was excellent. We re-negotiated a price with him after his initial one was so much higher than the ship's. We had a private tour for 4 people doing exactly what we wanted for the same price. We had a drive through the mercado, the chapel of peace for magnificent views, even looked at a house for sale (I said it was a custom tour). We went to one jewelry shop, saw the cliff divers from reserved seats in the adjoining outdoor restaurant, and had lunch on the beach at a place full of locals. We then toured the fort and the museum on our own before re-boarding. If you have not been to Acapulco, there is a day's worth to see.
Our Port was actually Puerto Quetzal. We were an hour from Antigua. PQ is an industrial port with a new-looking port store full of local merchants and artisans - they actually congregate around it as well. But there is no other town. You MUST secure transportation to do anywhere or do anything. We booked with the ship's tour "Antigua on Your Own" a bus trip to the old city and back with a guide on board. Worthwhile, IMHO. Antigua is an interesting old city with many derelict structures do to Guatemala being an active seismic zone. Worth a visit, but the street hawkers are pests. The worst I have ever encountered, with the exception of Tunis. As you disembark the bus, you are spoon fed into the Jade Factory for a movie and (they hope) purchasing. You don't have to do this! You are also approached by individuals wishing to acta as your paid guide for the day. I did not do this, but wish I had. We strolled around the lovely square, entered some shops, and had a beer (Gallo). Had a nice day, but it would have been better to know what we were seeing in some instances. It is an interesting country and worth a visit. There are ancient ruins (somewhat recently discovered) inland that were quite a distance. It would have been interesting, but was a very expensive plane ride.
This port is also an industrial port only (we were in Puerto Caldera, a last-minute change. I cannot speak to Puntarenas). Costa Rica is plain gorgeous, but, again, it is necessary to secure either a ship's or a private tour from this port. There is no walking anywhere. We booked with Okey Dokey tours with acquaintances ahead of time. There were 11 of us and I do not recommend "Charlie" from Okey Dokey tours. He provided no commentary - he was on his cell phone the entire day. We seldom knew where we were or why we were stopping. 8 of us did the zip line and he handled that part very well. He left out several things that were promised for the price. When we met him in the morning at the appointed time he put us in the van, drove us far enough away that we couldn't reconsider and go with someone else (we had not prepaid) and left us for an HOUR while he tried to get another van for another 8 people he had acquired at the port. We finally found him, approached him en masse, and he drove off with us after blowing an hour. He was just really full of it and we could never get a straight answer out of him. Parts of the day were lovely, but he failed to deliver on all that he had promised. I do not recommend booking with him. The country and the area and all there is to see I cannot recommend highly enough. This was one of the highpoints of the trip.
Cartagena was a surprise, and my favorite of the lot. Cabbies congregate at the port and negotiate to guide you for the day. This is a great deal and a safe deal as well. The city has much to see and they save you much time, wandering, and backtracking. Really an amazing place. The old fort, the old convent, the place where slaves were sold, the old, walled city are all worth a visit. The old city, particularly, is reminiscent of both New Orleans and Barcelona. Two lovely old cathedrals, the Bolivar square, public art everwhere and great shopping and eating. There are pretty stiff fees to get into both the convent and the fort and we had to pay this after booking our "tour" with the cabbie, so perhaps that can be negotiated ahead of time if you are in the know.
There is also the new downtown, as well as "miami beach" the strand of beach populated with condo after hotel.
I will mention that there was quite a "gendarme" presence in the city and that the cabbies/tour guides are reluctant to have you venture too far on your own. Not that far from Medellin and kidnapping is an known activity in the country so that is probably the reason.