I have troubles understanding what’s going on with one of my NPCs.
It’s the very first NPC I met in the world, she gave me a quest for patient treatment records. I completed it, and when I told her about it, there was a dialogue option to ask her come with me. I didn’t, instead checking another mission. After that, I cannot recruit her. She’s following me like a regular follower, smashes corpses, I can use bandages on her, and that’s pretty much it. She is not considered a follower - I can’t sort her armor, swap places with her, can’t even check her stats/skills because her dialogue is regular unaligned NPC dialogue, and so on.
Question 1: what are the conditions on recruiting NPC as a follower? At least for that option to appear in dialogue, regardless of success chances? I’m asking because when I check Dusk’s opinion, it is the most excellent i’ve ever seen: +14,-7,+28,-3. Yes, +28 in Value, we are apparently BFFs and we travel together but somehow she is not my follower 
Question 2: now I’m on her 3rd mission, that is “Reach farm house”. It doesn’t show mission marker on a map so I thought any farm house will do… apparently not. I’m standing in farm house (overmap says so and location in the sidebar too), she’s standing right next to me inside this house, but somehow mission can’t be completed. Do I need to find some particular farmhouse? I tried one the new ones with grapes stills and orchard, and one old-type, with horses and carriage shed in the back. They both don’t work.
I think for some missions the NPC becomes a temporary “follower” a follower in that they follow you around, rather than being your minion.
In the old days of the game, thats what a follower was, just someone whos AI was told to follow you around, and that code still exists for these missions, but probably causes problems with the new system and also causes confusion.
I think thats whats hapepned here, they are following you until you reach the farm house, but im not familiar with that particular mission.
Does it show any co-ordinates when you open the missions window? (M)
No, there’s no “target: (x,y)” at the bottom:
edit: I checked in game files, and the mission seem to be requiring “farm_2” which is the “survivalist farm” and is shown on overmap in green “f” letters contrary to regular farms and fields’ brown color. This should be probably mentioned in some way in-game. For example, iirc only this farm have barbed wire fence around the fields, maybe mention it in mission description?
That mission in the JSON has this …
"id": "MISSION_REACH_FARM_HOUSE",
"type": "mission_definition",
"name": { "str": "Reach Farm House" },
"goal": "MGOAL_GO_TO_TYPE",
"difficulty": 2,
"value": 60000,
"start": { "effect": "follow_only" },
"end": { "effect": "stop_following" },
"origins": [ "ORIGIN_SECONDARY" ],
"destination": "farm_2",
So it wants to find any farm_2
Farm_2 is the old style. open up data/json/mapgen/farm.json , its the first one there, with the large fields of vegetables, and a barn next to it. ( not with horses, but the one thats filled with zombies behind the metal garage door )
I think you need to find one of those farmhouses.
Yep, found it too, apparently at the same time as you were posting the answer 
Still, this should probably be hinted at in-game. Checked because there was one on the map, and it worked.
BTW, the “following” thing is really confusing. While she was “temporary”/“old-style” follower it showed “following” in light green text in shift-v window. Now that she’s my “proper” follower, it still says “following”, just in darker green. I mean, yeah, the difference is there… if you know there IS a difference, that is.