I spend most of my summer weekends near or at the beach or on the water and subsequently do a lot of
ocean/beach/boat shooting. Frankly sand is a way bigger concern than salty air a good gust of wind can kick up a lot. If you continuously dunk your camera in salt water you will have an issue but then again if you continuously dunk your camera in fresh water you will have an issue as well. Most modern cameras have little if any exposed metal anymore. For what its worth most of it is aluminum which corrodes (instead of rusting). I usually wipe down my stuff when I get back inside to remove any salty condensation but I cant say its ever been a real issue.
I have found that the temperature swings and high humidity near the ocean can cause fogging issues on humid days. This happened to me shooting the sunrise one morning. You can see in the
last few slides in this album. Other than that I have never really had an issue.
Get a tripod that you don't mind getting some sand on and always extend the bottom legs first. When you get home, hose it off, its aluminum, dry it with a towel and its good to go again.
Don't be afraid to get out on the beach with your stuff i know a lot of people are afraid of sand, but lets be honest, gear can (and often is replaced).
Dont miss a good shot because of some silly fear.
FWIW I dropped my Nikkor AI-S 300mm manual focus front first into the sand while birding once. I was careful to slowly pick it up, used my airblower to get the sand out, not a scratch on it and it still works flawlessly.
Regards
Dave