Protecting bike from salt and rust in commutes
So I just bought a vintage bianchi road bike with a steel frame and nice components. It's currently winter where I live, and this means that there is often the typical mix of slush/salt/snow/dirt on the roads. I've had issues with bikes getting damaged and parts not working in the past, and I would like this bike especially to be protected from that. The paint on the frame is still pretty good, not much damage is visible. How much should I be worried about the bike? I usually commute a short distance (>10 minutes) and then the bike is locked outside to a bike rack. When I am at home I keep all my bikes inside as a general rule.
What is a good set of rules/strategies to protect the components/frame? I don't want the nipples to seize, things to rust, etc. I also could potentially wash the bike but it would be quite a big hassle (no garden hose etc in my apartment).
Is my best strategy to just ride my beater mountain bike around or are there ways to realistically protect my bike well?