I built the fort I posted above with a particular goal, after I discovered the hill to the east of the wagon had a column of stone running down the middle I left the column intact and engraved it, then put staircases inside of it, and later decided to remove them and used dfhack to fill it with magma, but the lack of symmetry bugged me, so I whipped up another column with a layer of soil all around it and used the external soil layer to engrave it before up-ramp removing the soil scaffolds.
Edit: in the ss below you can also see the reason I filled the columns with magma, I forgot you can't pressurize magma, and initially had them linked up with the hopes that opening the floodgates would have the magma rush out onto the surface, but sadly that was not to be. I did achieve this effect later with two MASSIVE pistons which actually made enough of a mess to overtop part of the fortifications and allowed some magma to leak down the stairs and take out a single gear... disabling my ability to shut off the monster until I could get a dorf to disassemble part of it...
The natural column extended down quite a bit below the ground layer so I kept digging down and engraving the area around it, did the same with the manufactured tower and filled it with magma:
The box to the north of the main fort is an enclosed pasture accessible while the pumpstacks are active, with another open air cistern on top of it that dumps through bridges at the north end, since the magma flow wasn't reaching that part of the map fast enough.
Later I created the open air magma cisterns with fortifications around the rims to keep dorfs from wandering into them.
I linked the above ground cisterns to the below ground cistern I built and filled the hard way from the volcano. Then I designated a pumpstack and suspended it all, unsuspending from the top down so the magma flies straight up to the top when active. Linked them to a four wheel reactor I nicknamed the monster, because there was no way to stop it originally. Later I added doors in the chamber under the reactor WHICH STILL DIDN'T WORK, so I included a couple of rooms full of braking gears which link to the shut-off hatch for the monster.
When I first embarked I had a ton of olivine blocks which I used to make the first enclosure around the wagon and entryways, and later incorporated it into the design of the rest of the fort along with the dorfwash:
The area where the military trains had the area under it excavated, floors were put in place as needed, and fortifications around the edges, so I can keep them away from the ground level if they're training whenever I pull the lever and flood the world:
You can also see the engraved vomit stockpile/party room, I had a lot of annoyance from undead keas and eagles so I put a column of obsidian over the party room with soil in the middle, smoothed the column and removed the soil down to the surface, then put the statues in and made it the meeting hall. Later I learned you can just use tiletypes l 1 st 0 sv 1 to get it lit/above ground/outside...
The farm area was more than sufficient because I started the fort with a hard cap of 20 until I got it set up to my liking:
Part of the pumpstacks are visible there, as well as some of my original plan to build steel surrounds for the magma around the columns, didn't have enough steel ready so I went ahead with obsidian instead.
Oh, and the bedroom/throne room/dining room for Urist McLegendary, who arrived at the fort with maxed out stats and skills, was then wrongfully accused of being a vampire, and later made a Duke as retribution. You can also see the monster reactor there, adjacent his room, as it was where I first placed him to keep him away from the populace until he started showing signs of hunger and thirst: