Here's the reply from my questions. There is a fee for using the camp sites.
Yes, the regulation for hammock camping is included in the 2013 park compendium that can be found at http://www.nps.gov/prwi/parkmgmt/upl...an-version.pdf on page 20.
Are you talking about 100+ people or campsites? Our group camping area (Turkey Run Campground) is open year-round and can accommodate well over 100 campers, but must be rented on-line at www.recreation.gov . You can also make reservations for individual campsites that hold up to six people in Oakridge campground - also reservable on www.recreation.gov
Please call the visitor center at 703.221.7181 for further information about the camping options at Prince William Forest Park.
Have a wonderful week!
Prince William Forest Park