Michelle,
Congratulations on your upcoming cruise aboard the Disney Wonder! It's a beautiful ship with exemplary service by Disney Cast Members.
As in any port of call (including those in the U.S.), you should practice reasonable caution when touring. Leave your valuable on board, for example.
There is shopping near both piers. In foreign countries, you'll find that sometimes the market vendors can be more aggressive than those in the States. A polite and firm "no thank you" will be important if you wish to discourage enthusiastic salespeople. Review Disney Cruise Line's
safety info with your family so that everyone is a wise traveler.
Disney Cruise Line monitors ports for safety issues. For instance, we sailed on the Disney Magic in the Mediterranean in May 2010 with a stop in Tunis, Tunisia. This year, DCL opted to substitute a call in Sicily for Tunisia due to the unrest in Tunis. Safety of passengers on and off the ship is of great importance to DCL!
You'll find shopping within walking distance of the port in Cabo.
Puerto Vallarta has a beautiful boardwalk near the ocean. Disembark and enjoy some shopping!
Enjoy your Mexican Riviera voyage!