Using the same map world-gen (1 cavern, 30-50z from surface to SMR) as I'm familiar now with "The Wet Lancers" dwarf civ from the northeastern area.
It's the year 199, and 2 other dwarf civs among plenty of goblins, humans, elves, and at least 5 towers reside in this small world.
In chapter 1, "Ironborn: The City of Iron" the idea was to build in the middle with neighbors of goblins, humans, elves, and 4 towers. The open gate policy did not last as the 40+ undead sieges was too much for the first winter.
In chapter 2, Ironborn: Tower Defense" the idea was to build tower bunkers around 20 tiles away from each other. It is a sound idea, but the lack of personnel to carry out such a project left the towers unfinished and undefended when the goblins decide to invade.
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In chapter 3, "Ironborn Diaries: Tower Defender" spawns a new idea of a more epic goal. We start an embark, nearest the western most fortress of The Wet Lancers.
The goals are:
1. Build one main fortress, above-ground, walled, crenelated fortifications (yes, gated).
2. Build a tower bunker, one for each embark tile region to protect the roads.
3. Build "mine cart tracks grid system" over (surface or elevated) roads both north-south, and east-west.
Roads are around 48 tiles part, at at least 5 wide.
4. Equip and train an iron-wielding army.
5. Retire and repeat to a new, expanding to the west, connecting the roads.
Progress. In a 4x4 embark, a crossroad tower is build to house the wagon, with option to build 12 bedrooms above.
After measurements of the entire land are made, the fortress construction began. Fortunately, where are solid dry area to pass the aquifer.
Year 201 has come, and the population is around 50.
16 loads of magma-filled minecart began 6 smelters and 2 magma forges.
There are 8 marksdwarf from novice to adequate that have yet to go full time training.
The current focus is to furnish bedrooms for up to 120 population.
The expedition leader mooded a bronze legging, he now wears it and came the militia commander armed with a crossbow. He is still the Master Brewer.
Two other moods are both Armor Stands. These are placed on the surface, in the middle of the walled fortress, awaiting barracks training.
No sieges so far, and the humans traded with us. There is at least 1 tower neighbor.
I think 10 marksdwarves, and 10 mixed melee will begin training.
If towers are built, it will take a while to connect them underground as each will required breaching from below, and no underground drainage has been carved yet.