Walled Castle completely furnished inside, but with space for game play. I built this by myself, one person, and use it in my latest survival world. It evolved from a hidy-hole, and i just kept building on
This is version 5 of the base which turned into a castle. among other changes are more underground passageways and a small dungeon area.
This was built on a leading edge of a mountain top so you may want to place it in a similar setting, but it should work anywhere with terraforming (adjusting the ground around). I am using the medieval resource pack MISA 1.19 and recommend using this or similar for a more rustic feel.
The castle will spawn before you at the front entrance gate ground level NE corner.