Wow, sounds fun. Plus you have grandma to help!! I am jealous. If the kids are not picky, the hotel will probably do what they can to accommodate the little one with steam veggies and non-spicy stuff. I would stay away from raw anything. They all say the water is safe. My daughter just got back from an all inclusive resort in Cancun with raging diarrhea. She is definitely more sensitive than most, but so are little kids. There have been issues with raw tomatoes and jalepenos coming from from Mexico, so you just have to be cautious even about teeth brushing. Usually you can find out easily if the faucet water is okay. When I stayed at a dive resort in Belize, they gave bottled water even for tooth brushing. Resorts survive on their reputations, so they should be up front about it all.