Trap Pond State Park, in Southern Delaware is a nice wilderness retreat area that has it all. It features Hiking, Camping, Canoeing, Boating, Fishing, and has some great nature programs. From Trap Pond, It is an easy drive to both the Delaware Seashore State Park, and Fenwick Island State Park.
Trap Pond hosts the most northerly occuring stand of Bald Cypress Trees on the East Coast. It has great pavillions, and picnicking areas, nice cabins, and even yurts. A yurt is the name for a circular tent about 16 feet in diameter which is on an elevated wooden platform, so that anyone afraid of creepy crawlies may have fewer interfaces with those critters and bugs down below.
There are nice hotels and motels nearby for those preferring a more standard nights sleep.