Carolyn, my pleasure! You have some great ports!
First, here is a link to what one Cruisemate did in Zijuatenejo
We just walked about and also had a great time.
In Puerto Vallarta, take the shuttle van at the terminal into downtown and do a walking tour of the cathedral, shopping, the Malecon, the Rio Cuale area, and perhaps a stroll over the new pedestrian bridge to Los Muertos Beach for a great margarita on the sane (Burros makes some strong ones, and you get to soak up the beach scenery). The taxi back to the ship from the Malecon area is $5. By the way, if you can, pick up a Fodors Guide to Mexico, and it has a great walking tour all outlined for you.
In Cabo, you can book a water taxi right at the pier to take you around Los Arcos, Lovers Beach and onto the Pacific side. It's a 45 minute tour, and should cost $12 per person.
Here is a link to some ideas in Acapulco, including the fort (right across the street) and the cliff divers.:
My niece said and others concurred that the taxi drivers are very aggressive in Acapulco, so you may wish to book an organized tour here from the ship. My niece said if she had to do it again, she would have done that. We did the cultural tour, which skipped the cliff divers, but most all said they were incredible.
Here is a link of a post I did with lots of great Internet sites for port info. I printed out and bound as a booklet -- made for good pool reading:
Finally, my niece was also on the Star in November ... she highly recommended the restaurant that has the French name ... dangit, can't recall, but you'll know it. She did not like the Southwestern one (but of course, we are raised on SoCal Mexican food, which is darn good).
Hope this all helps, and please feel free to post any further questions.