Pro tips to clear out large pieces of land quickly while creating an easily defendable village
Just use gathering hut instead of terrain level field
Or whichever shape building best fits the way you want to remove terrain. Unlike the terrain level field, building level fields will disregard vertical height. As long as ~60% of the building is on flat land, it will let you place it. Gathering hut is 3×3 so the back 3 squares will end up completely in the ground and you can remove a 1×3 section at a time.
Just dismantle the hut and build last, rinse + repeat.
You can use this method to make enemies path around to a single entrance, and place a kill box there. Will upload an example later.