With the size of your group a private driver with a big bus is the way to go, child and all. Won't cost much and you can explore as much or a little as you feel like. Build your own crawl and move on from places you aren't comfortable with. I do know that it is also very common for parents to use babysitter/nannies referred by their hotel. Have a phone with you and you can be back at the resort in 15 - 20 minutes from anywhere.