When making a fort, i almost always do this:
I make a single long hall 2 squares wide. How long it is depends on the size of the mountain and surrounding land scape. At the end of the hall, i make a very large room for dinning, and I connect a room to the side and make it a stockpile for all foods, exculding seeds (Seed stockpile comes later). The I create a small hallway cutting off of the main hall and line that with rooms, I dont care how you make the rooms, but this is how I do it:
####
#B _ D
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# = Wall
B = Bed
_ = floor
D = Door
At the end of the small hallway, I make a turn in the hall, go seven squares, and make another small hallway going in the other derection of the first small hall. Line that with rooms, go to the top of that hall, lather, rise, repeat until your certain that you have enought rooms. After that, i make a small cut off area near the main door and build a down stairway there, then (after building a up stair way below it.) I go to the soil area (or near enough) and make gaint rooms to be stockpiles, somewhere in there I also make a farm, and wall off the place i got the water. From the hallway to the farm I make yet another cut off to get a seed stockpile. Out side I make some walls in the general area to put the trade depo, barreks (I know i spelt that wrong you grammer nazis!) and other things.
In a nutshell, it should look like this:
(P.S. The housing area in the top floor looks diffrent from what I described because these pictures were taken before I had finnalized the system)Thats how I always make my forts :3