With reasonable minimal care you have nothing to worry about. Wipe the blued parts down after use with a rag with some Rem Oil or Hoppes, or you prefered solvent.
Prior to use in inclement weather I use gun grease on the wood to blue gap around the action, and spray a durable metal protectant on the barrel. If you are out in the slop, pull the barrel off, towel dry and spray the metal down with WD40 (as a water displacement action). clean, and reassemble once warmed up and the wood is dry. I have only blued guns, and hunt a very wet climate (upstate NY) and prefer hunting the slop. I have never had rust on any of my guns.
W