It’s easy to want to keep this place a secret: nearly a square mile of green fields, eye-popping sculpture, groves of trees, and spectacular, tranquil views of art in nature, all within 90 minutes of New York City. But the experience at Storm King Art Center—to call it an outdoor museum is inadequate—compels you to share. And now, more than three months after it typically welcomes visitors for the season, it’s possible to visit again. After months in quarantine, there’s nothing like the site’s expansive sense of space. (Storm King…