An RV tech recently confirmed the issue of water getting behind the vinyl trim strip then soaking down the screw holes and rusting the screws out. I learned years ago, with water skis, that rusty steel screws are really the least of the problem: The Rust "Corrupts" the adjacent wood. So... Tapping a dowel in (given there's enough wood there to accept it) AND replacing screws with STAINLESS are both valuable considerations. I've used lots of those little dowels known as Tooth Picks. Wooden skewers might be good, never tried those...
