Lucky you! We go to Kauai just about every year. Best protected beaches are poipu beach park, 'anini and lydgate which also had the "worlds best playground" according to my kids. If your toddler is toddling around already, we find nice shells on 'anini and tunnels beach, if you get there when the tide is going down. We like to visit the sunshine (farmers) market for crazy treats like starfruit and coconuts, which they will open for you. And we can't get enough of guava juice and papayas. There can be lots of wind, if so pick up a kite, there is a kmart, walmart, even a costco. There are tons of neat bugs, geckos and plants to see. We discovered one plant that folds up its leaves when you touch it! And don't forget the shave ice - yum! I pack a picnic since our favorite spots don't always have food, plus little kids and restaurants are too much work for me. If you're hikers, you may want to bring a kid backpack, the trails can be steep. Have fun!