Chris said it right. It is all about rinsing and maintenance. A through-hull flush will make it a lot easier and you can get that installed for less than $300 at any boat shop or DIY for about $150 if you are not afraid of drilling through fiberglass.
I ride in brackish water all of the time and I've owned SS editions and standard with flush-kits. Personally, the SS series made no difference and it is all about upkeep. Now, I will say a galvanized or aluminum trailer is a smart move.