I just plan my oil changes before it gets too cold out or before it gets sloppy during melt. I don't change oil based on season.
I start to top off the washer fluid with decent winter blend and monitor tire pressur on cold mornings.
I keep an extension cord, window scraper, washer fluid, shovel and blankets in the vehicles.
Other than the above noted, I have a bottle of antigel in my 3500.
I tinker on the vehicles all year as needed so fluids are fresh, tires rotated, thing greased and so on. I am more worried about getting my snow fence up, snowlower tuned up and furnace ready.