After seeing a few little doors built into logs or houses, I decided to try one myself. Ultimately, I would like to plant a few out in the woods with a doodad inside for someone to find, but I carved my first effort into a rotting dogwood stump in the backyard.
First, I flatted the stump surface with a hatchet and free-handed the hole with a shallower recess to hold the door, then drilled out the bulk followed by chiseling–ended up being rather easy with the soft wood. The saw cut below comes from an earlier attempt to lower the stump.
Making this door required a lot by comparison. I split a small half of a log (chestnut oak fallen just behind the compost pile) and planed it down into a board. I transferred the shape of the door using a tracing, cut it out with a coping saw, planed more, and did final adjustments with a chisel. The set up looks like the creation of a drunk bachelor fairy from the old country, but I accept the effort.