Phenomenal Experience with this Phenomenon
Always remember, where the H2O pools may not tell you where it entered.
There are several entry points through the exterior skin, that allow the H2O to run down the inside of the interior skin to the floor in front of the door.
I once devoted much time and energy to replacing the door gasket (rarely the culprit and didn't fix my leak).
Start at the uppermost hole through your exterior skin and work downward toward the door.
Most of my H2O penetration was coming through seam around the top vent, running down the inside of the interior skin and pooling on the floor at the door.
Some H2O was penetrating the window adjacent to the door and adding to the pool.
Remember also: NEVER USE SILICONE CAULK. The one sin the Airstream gods cannot forgive.
2019 Flying Cloud 27FB
2020 GMC Sierra 1500 Crew Cab 6.2L Max Tow
Four Corners Unit WBCCI #5783