Alexander Duncan, estranged father to Marcus Duncan owns and resides in Sayv's Castle. A stone home that has too many past memories for Alexander to leave. This castle is nearly void of modern amenities and although it's not off the grid it can absolutely function without power if one is willing to sweep the massive home. A butler and maid service is a must here and Alexander is thrilled to have someone there to help him with the upkeep because getting down and dirty fixing plumbing is OK to Alex.
If you want to try this simple castle out note that you can't raise the walls to be taller or else you will lose access to the lower floors (due to the uneven levels for each section of the castles rooms)
Add a few mods to make playing way more fun.