I'm sure you'll get a lot of opinions on this, so let me be the first.
I'd suggest
Marine Clean to throughly clean the trim and
POR Glo to treat the trim afterwards. POR Glo isn't water-based. The stuff will last and the textured trim will look great for at least six months (POR claims at least one year) through any kind of weather you can imagine. I've yet to find anything better for exterior trim.
POR sells a lot of products in the old car restoration hobby. I even used their rust preventive paint to coat the underside of my basement bulkhead door which was rusting from summer condensation/humidity. Rust no more.
