Time to share

When Sarah decides to make a quilt depicting her favorite view from Mount Greylock, she hikes to the area, bringing her granddaughters, a sketchbook, and a camera. The girls videotape each other goofing off at the top of the hill, and later, Sarah notices something odd in their footage: a man, barely visible through the bushes, struggling with something on the ground. Who is he? What was he doing there?