Stone walls, moats, and scattered defended crafting stations. I got attacked by trolls a bit ago and they hit my house from outside the base. Minimal damage but it was annoying.

After that I put in two moats. One on the far reaches of my base where I intend to expand for farming and fun. I then scattered crafting stations in that area and built walls around them. Those two things drastically decreased my monster problems. I then set up another moat close to my base about 10 but no more than 15 metres from my wall. I extended my stone walls to my harbor and enclosed it all. I don't have any monsters getting in, my wolfs roam the perimeter freely, but I can't snipe deer or boars from my roof anymore.

It also took away from the view but I can probably fix that with some stone walls.