First of all, don't STAY in the Stone Mountain area (it's a lot rougher than it was years ago in many spots), although the resorts inside the park are decent.
There are lots of attractions inside the park. Here is the web page where they list them all:
Stone Mountain Park Atlanta fun kids family attractions laser light show riverboat cruises scenic train ride the ducks plantation tours skyride People tend to like the Crossroads old time village, as well as the Old South Plantation area. Once the weather gets warmer there is of course the laser show against the side of the mountain at night, too.