I stayed overnight at the Philadelphia / West Chester KOA to do some hiking at a couple nearby state parks (Big Elk Creek and White Clay Creek Preserve) during the second weekend of April. KOAs aren't my favorite (no other campgrounds nearby), but this one was pretty decent, and I got a spot right next to Brandywine creek. It's also very close to Longwood Gardens, which I also went to. It was sunny all weekend and fairly warm (mid to high 60's), but got chilly at night (40's).