Dunn's River Falls is a must tour to take and the catamaran trip which is usually offered at different times is great. There is a crafts bazaar at the top of the falls for some shopping. The closest shopping plaza to the port is about a 20 minute walk once through the gates turning left at the top of the street as long as you can put up with the locals wanting to take you on a tour! Just politely say no thank you and keep walking. Don't wear any jewlery or carry a camera. You can buy Jamaican Rum or Coffee which are great souvenirs. A tour to Sting Ray City on Grand Cayman is also a must do. In Cozumel I would skip the local ruins as they are nothing compared to those in Playa del Carmen or Chicen Itza. We have just taken a taxi to the Playa del Sol and had a great morning on the beach and there is a good crafts bazaar there as well with cheaper prices than in town. Taxi fare about $12 each way. There is a restaurant and facilities for your convenience. When you return to town be sure to stop into Poncho's Backyard inside of the Los Cincos del Sol at the end of the shopping district. The store sells everything and is very well kept and the restaurant Poncho's is a lovely respite for the end of a fabulous day in Mexico. Strolling mariachi's and great Margherita's.