Carcer City is based largely on Detroit and Chicago, and as we know: North Yankton is based on North Dakota. All technically part of the midwest...
If Michael stole enough money from each heist, he could probably wait a few months/years between heists. Who's to say that he didn't just move to Ludendorff after a big heist in another state? When the money starts to dry up, cue the start of GTAV.
I always assumed Michael lived in Ludendorff and robbed banks in the surrounding cities blind and then went back to Ludendorff. When you go to think about it, it makes sense to keep a low profile. Hell, I you were a federal agent investigating a robbery in Wisconsin, last place you'd think to look is a trailer park in North Yankton, right?
Not only that but Michael met Amanda at a strip club and evidently they grew onto eachoter, eventually getting married. So either Amanda's willing to marry any schmuck who's willing to ask or Michael stuck around to get sweet on her. They might've moved around though. If it was specifically mentioned in a friend outing with Amanda or anyone else, I haven't heard it yet.