DuPont Bike Retreat offers a wide range of accommodation options that can suit any group size. The site we used was site 8 and it's right on the pond. 4x4 is recommended to get down to the pond sites, but they also have hill sites which are great as well. This is spitting distance to Dupont State Park which is perfect for a weekend trip.
If you've never used Hipcamp, it's like airbnb but for camping! You can use the code CATEW8BCF14 to get $10 towards your first trip.