In the "Getting Started with Woodworking" video, the holes through the 4x4's were drilled from the back. That is, they start on the side opposite the precisely-positioned mark, and drill through to hit it. If they can do this, more power to them, but I can't drill through 3-1/2" of wood to emerge at a precise mark without a drill press - and not always then.
I'd intentionally made it oversize, intending to trim it flush. Trimming is a little more complicated than usual, because I needed to trim it flush on two faces. The end face extended a good 3/8", so I cut off most of the excess with a circular saw and the edge guide, then flipped the edge guide upside down to make a stable platform for the router. Aside from the use of the edge guide, flush trimming the edge face was unremarkable.