Well once you place enough workbenches in your area, enemies will simply stop spawning. Typically I do this with a Log Pole Fence on the outer area to make sure stragglers don't wander into the area, I also made a tiny house around each Workbench so they don't get attacked. It's the more efficient and cleaner way to make a safe base without having to make a ridiculous stone wall/trench setup. If you place enough Workbenches, even invasions will stop spawning enemies. Nothing will spawn, just complete peace.