The de-icers are deadly; I ride two, three times a week during the season. Camper is on more often than not, so a good wash on it often is surely a good thing.
But I think the killer is the under carriage. I've walked the steps of a man who's rig lived it's life driving through the salts, and it's brutal.
When I get home, I back up on blocks that I leave out all season. After the entire rig is parked (trailer and truck all get up on the blocks), I run a traveling sprinkler under it. Takes 6 to 8 hours and then shuts it's self off. I've tweaked the spray pattern just a bit, so it hits the entire undercarriage quite well.
The only actual 'extra work' each time, is pulling the hose back down the driveway before I back up and setting the sprinkler back on. Takes a minute or so.
I leave the blocks in the drive; the rear blocks for the truck are set in a hair so the trailer can pass over them. I just weave the trailer past the front blocks when first backing in. I'm sure there's better options out there, but this is the lazy way.
As far as the camper, we don't do anything else special. The WH stays lit throughout the season, there is a small electric heater in the bathroom that stays on low while plugged in. We keep it fully stocked with food minus the fresh produce, etc, that we might want. Because most of our over night trips are focused on sledding, I can go several trips overnight without worrying about dumping or re-filling the water.
Winter camping is the best; parking it just isn't an option for us.
'16 F550 CC, 4x4 with Link Ultraride air suspension, '18 AF 1150. Just so we can play with our snowmobiles, dirt bikes and fishing boat. And new 20' tag along...kayaks, bikes, mc's and extra water and food!!