How Much of a Plot Do You See in Your Head?

"I'm i stumble forward from way point to way point. I have a destination on the horizon, but there's a whole lot, of course, correction that has to happen along the way" "Sometimes i'll get to a scene, or find myself at the end of the book pulling what seems to be a rabbit out of my hat," he says. 'And oftentimes this is a good sign that something is ratifying the choices that i've been making'