We live about two hours from Lancaster, so when we want to get away for a few days, Lancaster is our go to place. We've tried a lot of the area campgrounds.
Our favorite: Old Mill Stream. Nothing fancy, but clean and close to a lot of the area attractions. We love the sites-large enough and shaded. A great place to kick back.
Next favorite-Beacon Hill. Clean and very friendly owners. We love the family farm that is across the street. There is also an Amish making hat "factory" at the end of the road, so you get to see a lot of Amish driving by. If you stay here, get a site by the road, so you can watch. This road is a dead end, so no other traffic. Beacon Hill is also close to the area attractions.
Lancaster attractions are spread out, and these two campgrounds are about twenty minutes from one another.