Possible Clues:

• Supplier of DC current that's too variable in basic lodgings to the west
• River that flows through Washington, DC
• River vessel with little old Scot at the stern
• DC current
• US runner returned old cap and waterproof
• Arlington Memorial Bridge spans it
• Mount Vernon is on its banks
• American banker in vessel with old raincoat on
• Part of West Virginia's border
• View from behind the Lincoln Memorial