You can go to city park I think they have peddle boats or at least they have some really cool huge oak trees to take pictures in. Also in city park there is a little story land and train.
That website has a lot of info on it. I haven't seen the trees that I like to take pics on. The big branches grow into the ground and back up again. There is more than I remember there. But living somewhere you tend to not take advantage of all that is offered.
You can take a round trip ride from downtown to the Audobon Zoo via the St. Charles street cars. Then take the riverboat back to the Riverwalk or Jax. Nawlins is not the most kid friendly city, but if only there a day the zoo and aquarium should do the trick.