I keep dreaming that someone will make a functional set of undercarriage plastic shields. Keep spray/mud from the tires reaching the majority of the nooks and crannies, mainly for the rear.
Once stuff gets into places like the taillight pillars, its not coming out with a simple rinse. But a plastic wheel well filler and plate from the rear wheel well to the bed end would help a ton.
My truck basically never sees deicing fluid or salt, but still rotted out the wheel wells from mud getting stuck where I couldnt see to wash it off.