I didn't mention that I will be in the U. P. of Michigan, right on Lake Superior. Trust me, it could get brutally cold. -15 and colder, and winds that can easily be 25mph sustained for more that a day.
I wasn't aware of the washdown concerns.
Maybe I should have been more complete in how it will be used. I won't start the truck and just leave it to idle fire a few weeks. It will get driven at least 30 miles a day. When is not being driven, I want to leave it running instead of sitting it off.
I used to drive a big truck in the great white north and I'm VERY familiar with your area, ( and a bus company I used to turn wrenches for had a lot of equipment around your area, and I remember well what they had to deal with ) and you are very correct in your concerns and most of these guys have no idea what they are talking about.
That icy wind blows through there at a rate that makes factory block heaters a moot point. Unless you have the truck indoors, they wont work.
I remember the Bus company used to have teh mechanics take turns coming out at night and firing up all the units to let them run for an hour and then shut them down and go home then the next guy would come in an hour later and repeat to control fleet fuel cost, but block heaters were useless, they'd be out there with a service truck jumping 2/3 of the fleet by morning if they tried to rely on block heaters.
The only kind of block heater that would be of any use to you would be a fuel fired one like an Eberspacher ( Espar) or Webasto and at current fuel prices, they might be worth looking into since you would only use about 1/2 gal to pre heat the truck, you can set it on a timer or remote and rig it into your blower fan to where it pre heats the cab and defrosts the windows before you get in.
Getting a throttle stick, or doing the bypass thar idles you up will be great, Those little dash knobs to adjust throttle speed that you push the center to shut down work great, best to set at around 1200 rpm ( I had an old Kenworth with a 1693 Cat and it had over 1.3 million miles on it and had never been apart, and had been idled any time the weather was cold or hot, its all in how you take care of them ) Just make sure that you bring it up to a high idle if you are going to do it, otherwise by the time you get out to , especially up there, and without a winter front, your engine temp will be down to about 80 deg and it will be barely coughing along