@ARE_you_kidding_me
I don’t think living in the Falcon was ever an option for Rey, as she had probably been there years (maybe decades) longer than the Falcon had, and the Falcon was kept in an (I’m assuming) private dock, whereas the AT-AT she was living in was abandoned wreckage out in the middle of the desert.
The Falcon had been in the possession of Unkar Plutt (the creepy alien dude Rey traded salvage to in exchange for food), who stole it from so-and-so, who stole it from so-and-so-else, who stole it from Han Solo (who, apparently, had been just waiting for it to become active in use again so he could track it down and take it back).