What are some fun tourist attractions in Eastern US?

My family and I are starting our vacation in Myrtle Beach, Sc, heading north to Hershey, Pa, turning west and finishing around the Springfield/St. Louis area. Along the way we can take detours, such as taking the outer beach of South Carolina rather than going straight through, or going as far north as Cleveland. Along the way, are there any fun attractions? Places like amusement parks, landmarks, museums, or just anywhere interesting.