We are buying a Montana 5th wheel and want to camp very close to the beach so we can walk to the sand and sea.
However, after chatting with several others on other forums, we have become concerned about the salt-sea mist, salt-sea air/wind and salt-sea fog.

Others have told us the above items are VERY corrosive to all metal parts, whether painted or not, including our tow vehicle, the lower frame of the fifth-wheel, our bicycles, etc, etc. It is even supposed to be rough on the fabrics in the trailer and tow vehicle.

They say the metal items will begin to corrode and pit within two weeks and continue to get progressively worse UNLESS washed regularly. (Few campgrounds allow washing vehciles and campers and I can't picture washing the undercarriage of the RV every week anyway.)
We figure we may have to camp well away from the beach to avoid the salt, since we don't want to corrode/rust $125,000 worth of truck and RV (on which we can barely afford the payments in the first place.)

So, 2 questions:
1) What experiences have you had with corrosion/rust, parking very close to beaches for a month or longer at a time?
2) What information do you have about "how far from the beach would we have to camp to avoid the above salt-carrying items?" (1 mile, 10 miles, 30 miles, etc?)
Thanks very much for any experiences you have had which may help with this concern.
Larry