I am fixing up a garage of mine with a workbench installed wall to wall. It currently has a plywood top that sticks out about an inch. I want to add an overhang (similar to kitchen countertops) underneath so that the top looks thicker. I figured I could add a couple strips of plywood underneath then flush trim the edge with my router, but I am unsure what I would I do when I got to the inset corners on each side. Is there a way to flush trim the edge even with inset corners? Thank you for your time, and I hope to hear back from you!

Logs are uneven and there are a few things I do to help make the layout chalk line more accurate. I have also read a couple of tips like holding the line down in the middle then snapping twice and using braided spider wire fishing line. I also do this: I hold a combination square with a level bubble while the log is on my work bench on the ends and pencil in a line on each end where I want to start a saw line.