Does a long term guest have renters rights?

I am trying to sell my home in Burbank, CA . My husband just passed away and his sister that was a guest that never left and ended up staying in an unpermitted guest unit now only stores her stuff in it,will not abide to many dates that we have agreed upon. Since there was never a contract or rental agreement and she never even paid any rent, does she have renters rights and could this be a storage issue since she the house has not had hot water for months and there is no gas in the unit and it is wall to wall storage?