Don't go screaming downhill based on my advice, but in my experience, rust doesn't attack as fast or hard as a lot of us think. All my bikes but one are steel, and two lived near the beach for years (one's a mid-'80s Trek tourer). My old Bridgestone mountain bike has been completely submerged in fresh water many times, and another steel MB sat out in salt air for two years when I lived on the coast. My Atlantis and Rambouillet get better care and have been Frame Savr'd, but I ride them in rain etc. without any special treatment.
None has more than superficial rust that I'm aware of, though I do worry about the fork on the Trek sometimes. It's my all-purpose, all-weather bike, with tens of thousands of miles on it (guy I bought it from rode from Indiana to Nevada on it, and I've had it almost 20 years). The other day I was bumping along over some rough pavement when it occurred to me that it's older than my kids.