This is awesome! But in this case, instead of introducing the human element, wouldn't it be (relatively) easy to make the entire apparatus self-driving and programmable? As in, mount this thing on a Roomba-like robot and give it a coarse driving path?
Getting a grip on the surface good enough to give you the control you need in the presence of sawdust is a lot harder than it looks at first glance. You might be able to make it work by putting a big magnet on the underside of the surface to attract the router, though.
I think that the magnet idea could work if you added 3 electro-magnets to the router chassis and made another chassis (to ride around underneath) with 3 corresponding ferro magnetic pads.
