Hill Top Medieval Castle.
There are many hidden redstone doors, an Elevator and rail through this one.
Check out the passage at bottom of the well. Also keep your eyes out for Stone buttons and hidden doorways.
Will work in Vanilla MC but has "Minecraft Comes Alive" (MCA} mod and people all through.
NB: I have found a fault in this schematic, the auto hidden rock wall doors on the railway at the front are not working. I will post a patch schematic to over lay this shortly.