Most important thing is to wash the underbody when the roads dry out. This will help control rust as best as possible. Many coin-ops can do this.
As far as winter prep goes, I can't afford a beater and FR-S is my daily driver. I enjoy detailing so I go a bit farther than most --
Prep, in order:
- Clay bar (clean large bits stuck in paint)
- Klasse AIO (chemical cleaner)
- Klasse HSG (heavy-duty acrylic sealant)
- Collinite 845 (heavy-duty wax)
This gives 6+ months of protection under good conditions, and seems to last long enough to survive a Chicago winter.
To clean the car depends on if you've got a garage or not. I throw a jacket on and do the GDWM with hot water and ONR Wash & Wax, it works marvels.
If you don't have a garage to wash in, it's going to be tough. Regular touchless washes will easily halve the time of any LSP, but there's not really any other option if you want to keep it clean.