Will you be staying in the heart of old Savannah or outside of town?
Considering the ages of your kids, it might be fun to do a carriage ride or the trolley tour. Good way to get around the city without wearing out the kids and they might enjoy the excitement of hopping on and off at different spots.
http://www.trolleytours.com/savannah/kids-corner.asp
Forsyth park is great. Beautiful fountain for family pics and playground for the kids to burn off energy before hitting the road.
I can't remember any specific restaurants to recommend, but it is a great city for wandering. Have fun!