We stayed at Nickerson State Park 7/25/13-7/28/13. It's a great place to set up a base camp in order to explore the areas on Cape Cod, within the park and the beaches. Bikes are a great thing to bring as much of the area within the park and surrounding areas are bike friendly. Additionally, the Rail Trail is nearby for additional great biking.
The sites are a good size with lots of trees for sun coverage. The bathrooms are semi clean (we stayed during a very rainy couple of days) but average for any state park. The park was very quiet at night. We were very surprised that by 9:30pm there were few campfires and very little noise.
The camp store is about average and they close relatively early around 8:00pm each night. There are no facilities within the campground to wash or dry clothes. We stopped at Orleans Coin Op in Orleans and quickly left due to the rudeness of the person in charge of the business.
Nickerson State Park is a great place to explore and camp while enjoying the beauty and uniqueness of Cape Cod.