Last I checked plastic wasn't affected by water of any type.
JK, just trying to start some trouble here.
It would probably be a good idea to clean and protect all the metal parts with a good oil like CLP. Perhaps even use a lite weight gun grease on all the moving parts. That should keep water out. After your trip, strip it down completely and clean/re-oil everything.
So long as you don't have constant exposure to moisture I would think you will be alright. Remember that cleaning EVERYTHING afterwards along with oiling it is important. Do that as soon as you get home, even if you don't fall in cause some moisture will probably at least be present.
Have fun on your trip