Prince William Forest Park (http://www.nps.gov/prwi/index.htm - for those the aren't familiar with it) up until yesterday did not allow hammocks. Fortunately that has changed. I just got this email in regards to an email I sent a few days back regarding the policy:
The management team discussed the camping hammock policy for the Chopawamsic Backcountry. The 2013 Park Compendium will allow and encourage the use of camping hammocks in the backcountry campground. Theses camping activities are still confined to the defined campsites - and some sites may not include trees that are appropriate for this activity.
Please stop by or call the the visitor center for more information on camping opportunities at Prince William Forest Park.
If you have further questions regarding the policies at Prince William Forest Park I would be happy to connect you with the Chief Ranger.
Right now I am thinking that this might be my first overnight hammock camping stop since it is close to home (minutes away).