In a large mixing bowl, thoroughly combine the squash, onion, red pepper flakes, olive oil, pasta, cream cheese, and milk. Pour the mixture into a 9x13-inch foil pan. Top the dish with panko breadcrumbs and cheddar. Stack 4 large sheets of heavy-duty aluminum foil, and place the pan in the middle. Cover and wrap the foil pan tightly so that no steam or juices escape. Bake in the fire pit on top of a grill grate for 25 to 30 minutes, until the squash is tender and the cheese is golden brown. Serve warm.