We've camped on the Gulf Coast in the past with our Class C. Most of the surfaces dealt with the salt spray just fine; but our tow bar setup was almost amazing in its ability to rust more (noticeably!) every day....sigh.
Personally, as someone who lives in a state that uses copious amounts of road salt in the winter - the salt spray from the ocean is stickier/greasier and does more damage?
Now we're snowbirds about 5 miles as the crow flies, from the Atlantic, with 2 barrier islands separating us; and I still find that salty/greasy film on my windows....