I have some advice based on staying there when our kids were little (3-4 years old.) We put them in sneakers to make the dune walk and packed sand shoes/flip flops for the beach. The sand gets so hot for exposed tootsies, but more importantly, sneakers protect them from the occasional but painful cactus and burrs that are present along the paths. Put some baby powder in the beach bag to help wet/sandy toes get back into the sneakers for trip to the house. Have a great time!