the beach, probably the most beautiful in the country are on the emerald coast of the panhandle. From Georgia, I recommend Destin. Sugar white beaches with clear and warm emerald water. You could also do Panama city, but it's more crowded and touristy.
If you want to see history and the old South, Savannah is nice. It's interesting and cozy, but not super for kids for more than a day or so. I like Savannah for romantic getaways.
Let me know if you want more information.