It's not realistic at all, IMO. But...
What I was saying, inarticulately, is that if she left with someone local AND was with them now, let's say in Kansas, both that person (and Abby) would be missing from North Conway. Then, it follows, that person would be able to carry on with their everyday life in Kansas, as Abby lies low. As far as I know, there is no one other than Abby missing from North Conway.
And, I suppose, if Abby is being held against her will by a local resident LOCALLY, then they could get away with it (like AC did for so long) but most likely they'd change their pattern enough for someone to notice. IMO.
Nothing you say is inarticulate, ever

You jogged my noggin right there - Something that Chief Wagner and JY said in the Presser about the letter;
Chief:
"In a manner that she reached out previously to them" @
"anybody that may have somebody new in their community that...
moved into a home recently* that has a young lady living in their house just please reach out to us and give us that information."
Jane Young:
"we have been able to confirm that she has no source of income... "~
"she is not out there alone she has somebody who is either helping her whether that be a friend or what we fear is a foe"+
"if somebody has Abby we implore you to make that contact. If it's a good citizen, a good samaritan who has her and thinks that they are helping her I can asure you that you are not." ^
http://www.myfoxboston.com/video?clipId=9607183&topVideoCatNo=238258&autoStart=true
@ - This is what you open with? I know it was short notice but JY didn't even get a chance yet to say that there is a letter...
* - where did that come from Chief? You get the Monk in me all aflutter. I put up my hands and look around the room and start rearranging things on my desk. So is there some kind of intel (notel) that they relocated and go to Church, etc?
~ - Except if she had a new ID and was getting paid under the table.
+ - Bingo. Especially after all this time. She needed a whole new wardrobe. Who can live on the street in the same pair of underpants for 3 months? Even a shelter would know to call LE by now and make some kind of contact.
^ - You must have a reason for making that reference and it had to have come from the letter.
Don't get me wrong I am not bashing LE. I think the Chief is doing things his way as much as he can. I can see the frustration in each of them - for different reasons most likely. I just can't wrap my head around this good citizen theory. But a lot of time has passed since that 'letter' hasn't it.