Really the big threat with the boat is salty carpet and wiring. Saltwater boats tend to have better sealed connections and shielded wire. Any salt gets into a connection it's going to have issues down the line.
Biggest issue of all will be with the trailer, if it's a painted trailer not designed for salt it will get tore the heck up. You might get away with washing the [censored] out of it with that salt away stuff but miss a spot and cancer will start in no time, if it gets inside the trailer it will eat it's way from the inside out.