well good news I discover how to store items... using Tweak. All I did was check on occupancy's 14-blood which cause any item on that tile to stay there when you leave
...built a first house for my adventurer
It was 10x10 stone hut with cellar and a 20x10 crypt.
...
EDIT: OMG even reclaiming is so easy when everything does not scatter everywhere...
Holy crab apples! That's awesome!
Now all that's missing is a way to combine DFusion with DFMode in a way that allows swapping between Fortress Mode and Adventure Mode without all those unpleasant side effects.
I don't suppose there is a way to prevent our pets and creatures from dying after Abandon fortress, is there? (Perhaps changing the ownership or friendship before Abandon?) Or maybe a way to prevent our dwarves from leaving the site area after Abandon? (Maybe by changing the parent civilization or something beforehand?)
I'm looking forward to the day when we can "Retire" a Fortress without actually Abandoning the site. And I'm not the only one:
'Retiring' forts is a crazy popular suggestion. Just below gunpowder and steampunk in it's perennial nature.
Ok, from various notes from Askot and Rumrusher, I have successfully "retired" my fortress - and it doesn't seem to have any bugs so far:
What I did:
1) used DFusion tools->"prevent items from scattering" function to "fix" parts of my fortress (basically moved the cursor over every floor, using "protect block around cursor" because I couldn't find a way to find the x y coordinates).
2) ran DFHack's dfmode, selected Adventure Mode, Direct Control
The screen will go black at this point, hiding most of the map.
3) used DFusion tools->Change Adventurer, selected a dead goblin (one of the hundreds in my refuse pile). I selected a goblin because my dwarves had scrolled off the top of my cmd window, but any dead entity will do.
4) without closing DFusion (i.e. pressing enter) go back to the fortress, ESC and save game.
5) Quit DF, restart it and reload. You will now be in adventure mode, possessing a dead goblin. It will now say "You are deceased."
6) Finish out to the main menu
7) Start a new adventurer, visit your old fortress to verify
The old fortress still has its old dwarves, and they act like normal townspeople (answer correctly to "Surroundings", which means they consider the fortress their home). I couldn't recruit my old militia, I guess due to insufficient fame, but was able to recruit a weaponsmith and a bowyer.
What's more, the fortress acts like normal game Mountain Hall, and I can retire my adventurer there.
Still have to test a bunch of stuff (reclaming, etc) but so far it looks like it's working correctly for adventure mode.
Edit: pets seem to be dead (can't find any alive) although the merchant caravan's animals are still alive and wandering about. I guess I have to stuff them in cages and use Runesmith to remove the tame flag before switching over.