Brazos Bend should be beautiful this time of year.
I have not done much fishing there, but have seen others fish. Honestly, If I were taking kids along I would stop by Academy and pick up some worms and bobbers and spend the day reeling in bluegills.
Watch for snakes and leave the alligators alone. Keep your distance. I've seen people try to get right next to them to take pictures. That is incredibly foolish.
While you are down on that side of town, check out the Varner Hogg Plantation and George Ranch Historical Park. They are both close enough to Brazos Bend to merit a visit and I believe they offer an incredible glimpse into Texas history and heritage.
Also, if you ever get tired of the crowds at Huntsville, Livingston, or Brazos Bend dont forget about Stephen F Austin State Park in San Felipe, just west of Katy. This is another great park with excellent historical sites nearby. SFA SP doesn't get the number of visitors it truly deserves.
[This message has been edited by PineTreeAg (edited 5/7/2013 3:09p).]