[Boodar]

Damn if your that desperate wait till they go out sneak in and it.ll be on a sticker on the router...
Only joking of course ...( Honest ) but it sure is faster than any other method...Lol , maybe a bit of social engineering? use your imagination.
Bombard the AP with aireplay to deauth, then after a day knock on the door and tell them you work for telecommunications and there's a problem in the area with some certain routers/wifi, ask "Do you have a problem with link dropping out?" then go in and fix it for them,Job done. That was just an example, but you get the idea, just think out of the box most of us do.