I take things on the cautious side and being broke down in the middle of ‘no where’ has its disadvantages. You may be able to communicate with someone (sat phone? amateur radio?) and end up waiting for hours for help or just waiting for someone to drive by, so as Paul said it is a matter of survival at that point.
In addition to Paul’s suggestions, here is what I would carry if I was driving up through Canada or Alaska;
Winter front (if you don’t have one, contact
Alaska Tent and have one made)
2 fuel filters, an extra oil filter and coolant additive unit
At least 2 gallons of oil
Howes + a gallon of diesel fuel in a proper container
A filter wrench (ever try to get a fuel filter off by hand in sub-zero temps?)
2 of every fan belt
A large propane heater with a few lbs of propane (not for the cab/sleeper by the way)
A heavy tarp (not plastic)
An emergency blanket or maybe three (they are cheap and take up no space)
Heated gloves and socks and rechargeable batteries with a recharger – you can’t wear a sleeping bag outside, can you? (OH and if you really want to get fancy and want to spend some money, go get a
Gerbing heated suit)
Make sure that your tires are in good shape, if you end up on gravel roads, you may tear up a tire or two.
Maybe this is just me but I would also get as much info as I can about the engine if it cr*ps out on you and spits out fault codes. With Cummins they have a chart you can buy at most Cummins dealers that list the fault codes.
AND tools – make sure that you take about 45 minutes to go through your tool box and make sure you have the right tools to do the job. It is a pain in the a** to find out that you have a 9/16th wrench when you need a 15mm wrench and you can’t just take that nut off to get to something you need because you don't have a metric tool on the truck. Keep at least two sizes of adjustable wrenches in the box and a long ratchet for leverage. Also get a couple long LONG screw drivers (like 2 feet long) for prying things.
As for operations, I would consider changing the oil and all fluids if you are going to do this for a season and go to a synthetic lube for everything. This will allow the components, like the rear axle(s) not to freeze up and damage anything.
Get your coolant checked and if the engine has an additive canister, replace it if it has been more than 5000 miles.
Keep the truck running if you can but remember that if you sit for any amount of time, there is a rear axle(s) that the oil does not get heat from any source and if it is frozen stick the heater under it and heat it up. Also just as a precaution, make sure that the brake cams are lubed up right.
OH I almost forgot, make sure that you have antifreeze in the air system - some trucks have air driers and need some antifreeze. Not sure anything beyond that.
I know I am missing something.