Puerto Vallarta would be a good place for the jeep excursion, with its lush vegetation, mountains and rivers.
Cabo San Lucas is a good place for snorkling and water sports. The Pirate Ship is fun; it's not entertainment-driven like the one in P.V. You actually sail out to open water, with some spectacular views of Los Arcos; and it is combined with a snorkling stop.
We very much enjoyed the walking tour of Old Mazatlan. Do it in the morning before it gets too hot; then you can gorge on shrimp on Stone Island, a short water taxi ride from where the ships dock. Or catch the Papantla Flyers, great shopping, good food and beautiful beach at the Golden Zone, a 20 minute open-air taxi ride from the pier.