This is my last kingdom, Burg Eichenstein. It is not very big, but quite dense.
The population is 17 but easy to increase. It is quite stable. Played on peaceful. Everything is built using ground floors and free placed blocks.
It has one main problem. At night it suffers from a strong lag. The speed change is very noticeable at dusk and dawn. It might be a memory leak.
Another bug is that some blocks, although built at different heights they count as if placed at ground level. As far as I know those blocks were never in contact with the ground level. The game set them like that. Use the slice button. They are easy to spot.
One last curiosity. One log of wood ended up under the ground. I have no idea how it got there and never gave any problem. I finally destroyed it with the console but I still have old saves in which they are present.
Actually I still have saves for nearly everyday from the beginning if needed.
Hope it helps.
Have fun, Kyth.