Hi, Jill!
Although I haven't personally participated in the
Las Caletas Hideaway Port Adventure, I did experience several shore excursions hosted by the same tour operators on the Mexican Riviera -- Vallarta Adventures/Cabo Adventures. Of all the ones we experienced, this company really had the corner on hospitality and the attention to detail -- which Disney guests become accustomed to on the ships.
There's a lot of good information on DisneyCruise.com about this Port Adventure, but to give you a little more insight into what there is to do, you might want to visit the tour operator's site at www.vallarta-adventures.com. You'll also be able to see a good photo of the catamaran -- which is a relatively large vessel. However, as one mom to another, take my advice and feed your little ones early that morning on the ship. It's a long way to Las Caletas, and the water can get choppy. There were several guests on our boat who lost their breakfast that morning and taking a motion-sickness tablet or wearing accupressure bands may have helped. I think it helped that we had eaten so early, kept hydrated and continued to look outside the boat.
You will more than likely have to be tendered from your catamaran to the beach, and you may even have to get wet when you step off the smaller boat. Wear clothes you don't mind getting wet -- and better yet, wear your swimsuits underneath your clothes. We also wore Chacos or Keens which we could take off or put on at a moment's notice. Bring a day bag with sunscreen, towels (provided by Disney just before you step off the ship), bottles of water, plastic bags and other essentials. Slip a few packs of crackers or cookies in there, too -- just in case.
Let me know if you have other questions. Have a wonderful day and a magical vacation. Bon voyage!
Andi