The sunroof drains run from the 2 front edges of the sunroof frame through the A-pillar to the back of the front fenders. The rear hoses run along the C-pillar, through the trunk (behind the quarter panel upholstery) and through a horizontal ledge in the quarter panels to the outside behind the rear bumper.
The best way to clean them out is to (gently) blow some pressure air through the pipes. The front drains are rather easy, the rear is difficult...
Is it possible that water comes leaking in from the door? There has to be an anti-water-plastic screen stuck behind the door panel. Maybe this screen is not good anymore (open at the bottom) and water comes leaking in from here?
with a minor 600+k