I have been to P.V. many times and for as long as a month at a time. P.V. is a beautiful and extremely safe city with a lot to do and see. If it were my first time, I would just take a cab into the middle of town and go exploring. This is by far the best of the three ports for shopping. This port also has excellent examples of true Mexican culture. Despite the many Americans living there, it hasn't been ruined like many of the coastal cities of Mexico, I.M.H.O.
There are many outstanding restaurants too, in case you want a bite at lunchtime.
Just ask the cabbie to drop you off at "The Cuale." You can explore most of the city from there. Also the bus lines are excellent and cost almost no money at all. Every bus line runs with a frequency of about ten minutes. (We should be so lucky to have their public transportation system.)
A walk along Los Muertos beach is very fun as is a walk up the Cuale and through the Zona Romantica. If you just want a beach adventure, you might choose to take a taxi to Sayulita or Piedra Blanca or if you want a very rustic beach I would choose Yelapa. This beach reminds you of Gilligans Island because there are no cars and the only hotel is a small hotel of little grass shacks. The pool here made of boulders is great.
If you don't mind adventuresome cab rides, take a taxi up to Las Carmalitas Restaurant for lunch. It is literally near the top of the mountains above Banderas Bay and offers a view of P.V. that few cruisers will ever see. They grow their own chickens and beef and the food and service in this "palapa" style restaurant is amazing. While you're eating, the chickens (and the dogs) will walk right through the restaurant at your feet. It is a wonderfully "Mexican" experience.
Or if you are shopping, onsistantly "Mariscos Polo" has the freshest and best seafood in the city at very affordable prices. This place is frequented mostly by locals, and is clean, well run, and has deliscious food. Their shrimp and or Pulpo burritos are like nothing you've ever had stateside. Mmmmmm! The whole fish cooked in butter and garlic is quite good too, as are the salads. Polo, the owner, is one of the kindest men I have ever met in my life. (Margaritas here are excellent too! Remember this place is not fancy, just good.)
Other great lunch spots, if you want a bit more upscale, are River Cafe, Le Gourmet, La Palapa, Casa Adobe. El Torito is great for ribs and steamed shrimp or Rito's Baci has good Southern Italian food., the list of great places goes on and on.
Although the Malecon area is fun to see and walk through, the better restaurants are elsewhere in most cases. Especially if you don't like being hustled bu hucksters.
Anyway a day in P.V. will only let you know you want to come back for a land cruise when you can really see all there is to see.
Mazatlan is a good place to take a tour. I enjoyed the Colonial Cities tour a lot. I like getting away from Mazatlan whenever I can.
Cabo is very accessible on your own. There are lots of tours available from the dock that will give you an array of choices at far less money.
Needless to say my love on this itinerary is P.V. The other ports are fun too but do not compare to Puerto Vallarta in my humble opinion. Feel free to E-mail me if you have other questions.