I also park my Jeeps during the winter months due to the salt.

My daily driver is a 2002 F350 regular cab with the 7.3 PSD and I plow a lot of snow with it... when we get snow.
Anyways, I have a few tricks I use to keep the body clean.
1. Car wash with underbody flush at least once a week when needed or after plowing.
2. I also flush out any salt on the underside by hand with hot water from the shop.
3. It gets parked in the heated shop every night. I also run a dehumidifier in the shop during winter to remove the moisture laden air. When needed, I will warm the shop air to about 75 degrees to dry out any moisture and then open the overhead doors to dump the moisture saturated air.
4. I broom out any water on the shop floor.
5. I also roll down the windows of my truck each night. This allows an opening between the glass and weatherstrip to vent the moisture inside the door. This also helps dry out the condensation that occurs on the cold metal after it is brought into a warm moisture environment.
6. I also use a product called Fluid Film to keep away the rust on the underbody. Oil pans on the 7.3's are known for rusting through, but I have been spraying mine at every oil change since I purchased it new. Fluid Film works great!
I would like to drive my Jeeps during the winter, but it's not worth it up here where they use this much salt. The truck is a great winter substitute and I enjoy using it almost as much as the Jeeps. My truck is by no means in perfect condition, but it does look much better than many of the plow trucks out on our roads.