You could definitely do 2 days at the par, maybe even 3 if you like roller coasters and the like.
The kids and I usually get to the park in the morning and do some rides before the water park opens. We then spend the afternoon into the early evening there. Basically, the hot part of the day is spent in the water. We will then do some more rides or take in some of the shows that they have until we go home.
If you like some civil war stuff, there are some historical parks in the area too.