We just returned from the Costa Rica trip this past Tuesday. It was really a wonderful experience. Our guides were extremely nice and personable. Everyone on the trip had kids so our daughter had friends within the first couple days. The other travelers were also extremely nice to be with and made the group experience that much more enjoyable.
Both of the destination hotels were very nice and well appointed. The rooms were large and comfortable. The food was good and since it was Disney, there were usually kids menu items everywhere we went.
Advice:
Take plenty of swimsuits. While we were at Arenal the weather was very pleasant 65 to 75 Fahrenheit, however, it was rather humid. The air conditioning in the room never really had to run since the weather was so cool. Therefore, nothing would dry.
Don't carry a lot of dress, dinner type clothing. Most of the meals are casual, you could get by with a couple of business casual type outfits.
Ask me any other questions you might have. I love talking about this trip and am probably already boring my friends.....