I have a friend that bought a 96' 35 Lightning new w/ a black painted Myco in 1996.
He uses the boat 90% in the salt.
When he's done with his day trips in the salt, he swings the boat & trailer by the lake & dunks it all in, flushing everything.
Then he whips the rig home & drys everything off.
The Myco still looks brand new.
However if that seems like too much work, I would go aluminum as a painted trailer would look good for about 2-3 seasons with 100% salt use, imho.