Your kids will enjoy them immensely. Suggest you bring goggles or sun glasses for them to protect them from flying dust particles. Probably by the time you come the Cueva de la Maravillas will be open. Don't miss that one. Also see
http://dr1.com/travel/juandolio/ and check out the links to nearby La Romana and Boca Chica for more things to do. You may consider a city tour to Santo Domingo, too.