Landlord Adam Rice, standing in the lobby of one of 657 Congress Street, is being groomed to take over his family’s Apartment Mart business. The 62-year-old Portland company has 300 units in the area. Story by Tux Turkel/ Staff Writer Photos by Whitney Hayward/ Staff Photographer T he apartment is clean, but modest, with two small bedrooms up, one bathroom down, a kitchen and a living room. It’s located upstairs in a 115-year-old building, on a side street within sight of the Portland Expo.