I think you are always going to get some water in the doors. The key is to make sure it can drain out and dry in there.

Just make sure the door bottoms (on the inside) are very clean. Gently scrape the crud out of the crevase, even vacuum them if you have to. Obviously, keep the drains clean too. I usually fabricate a new plastic sheet to hang on the inside of the door to replace the heavy paper that came from the factory. This keeps the backside of the interior door panel from getting wet.

I recommend against putting sound dampening material in there. To me, that is just going to trap more moisture and make things rust even quicker. It's tough to make a 140 quiet. They're just noisy compared to modern cars.

Unlike George, I don't remember ever coming across a roller inside an early 140 series door. I haven't had scrapers on my doors for years and the door bottoms are still fine.