But, granted you arent spending alot of time on the road (a day or 2 travelling) and wash the trailer (and your poor truck LOL) thoroughly after each travel youll be fine. Rustproofing, undercoating, ect all help. But as long as you wash the unit in a timely manner after it sees salt their is little to no harm done.
salt isnt some magical chemical that instantly vaporizes steel upon contact. If you wash it off in a timely manner their is no ill effect. if you allow it to sit on the metal, especially in a moist environment, your going to have some issues
If all of us that lived in the road salt washed our vehicles even once a week, you wouldnt see a fraction of the rust on vehicles. everyone complains about road salt, but i know more than a few people that wash their vehicles once a year!
'14 XLR 395AMP
'16 Ram 3500 DRW, 6.7 cummins w/aisin trans and 4.10 gears