I placed the aluminum skin on the door and secured it long enough to use my RotoZip to route the edges for a perfect match to the door. My bit kept clogging with aluminum until I squirted a small bead of penetrating oil on the aluminum over the route to be cut. No more clogging!

I then drilled a pilot hole in the window corner and routed out the window opening. Test fit the window to insure all is well. So far so good.
Applying the Aluminum