It was back in 1967 when the Congress chartered the National Park Foundation to serve as the official charity of the National Park Service, and over the decades it has raised millions of dollars for the parks.   The Foundation is in the midst of its Campaign for National Parks, a billion-dollar campaign that has already raised $815 million. A big chunk of that total came from a recent $100 million grant that greatly moved the foundation closer to its billion-dollar goal.   To discuss the campaign, how the money is raised and where it’s being spent, we’re joined today by Will Shafroth, the president and CEO of the National Park Foundation.