Jeff - How do you do things like that? I've been playing for a while now, but I don't know how to order and organize construction/workshops for things like that.
This latest castle is square with 21 square long walls between 8 square towers. Each tower has a stairwell going up 8 z levels to the top, and down 3 z levels into the ground, broken up by hatches to prevent falls. The center of my castle has a tower with 4 stair wells going down all the way to the last z level, and up 3 z levels where they come up directly around the trade depot. This is where the bridge from the fortress connects to it. (The bridge comes across on z level 4, but drops before entering my tower, which gives the balista in the tower on z 4 the ability to fire straight down the bridge.
Anyway, the first 2 z levels under the castle have the same dimensions, mainly because the moat goes down that far. The moat is 2 squares wide and 2 z levels deep, except where it runs through the two western towers to run 4 water wheels inside those towers on ground level.
The way I set it up is that prepared food, booze, finished goods, and stone are stored near the center stairwells, and raw materials are run up and down each tower stairway. So seeds and plants are stored in one tower, with appropriate workshops and kitchens near that tower, dyers and looms further out from that towards the center, and clothiers workshops right next to the center. Each tower is similar, but for a different material, even the refuse tower, which is near the butchers, tanners, and leather workers. That tower was channeled all the way down 4 levels and had floors put in with a 2x2 floor grate in the center
The 3th level underground I build custom for workshops as I need to expand. I haven't expanded this one too much yet, but part of my plan is to dig a tunnel that goes under the military fortress, stack wood and goblin weapons at the ground level on floor grates there, and drop it a shaft to that level, so I can bring them inside without endangering any haulers except my woodcutters. If I do that, I'll probably move all of my smelters to that level.