Running more than 160 pages, the National Park Service Management Policies provides park managers with quick reference to how they are to manage their units, what uses are appropriate, and how to usher visitors out of the park when Congress fails to fund the National Park Service. But the Management Policies, which last were updated in 2006, also leave much to interpretation and exception.

How do you decide on a vacation destination? Which route to take, attractions to visit and where to spend the night? No doubt you use online info. Star-ratings. Pics. Travel blogs. Information is short and to the point, like this 2015 review of Mammoth Cave:

National Park System units from Mammoth Cave National Park in Kentucky to the National Mall and Memorial Parks in Washington, D.C., were shutting down Friday in advance of a massive snowstorm predicted to dump upwards of 2 feet of snow on some parts of the East.

Joppa Church in Mammoth Cave National Park is now designated as a day-use area. Vandalism to the church building in the last year has caused the park to limit its availability to the public to daylight hours only