Diesel Fuel Availability

The North runs on diesel. The issue might be distance between availability. No harm in carrying a 5gal jug spare if you don't have a second tank built in.

The second tank is really nice. We can do 500 miles towing on mostly flat without breaking a sweat worrying about the next chance to refill.

^ Like PA, it would be wise to carry a jug or 2 for potential "what if" moments.
But in my trips up the Alcan or driving around AK, I never busted the spare fuel out.

My first trip on the "Alcan" as it was called when I was growing up was in 1976 or '74 (I forget). Followed in due course by a few trips up the "haul road" to Prudhoe...all interspersed with routine trips on the Alaska road system when a lot of it was gravel and in the winter when I infrequently saw the old gas station thermometers reading -40 or colder. All of which left me with a healthy fear of running out of fuel when either: i) it was 200 miles between fuel pumps; or ii) it was below zero. To this day, I can't travel outside of the Anchorage-Palmer-Girdwood-Willow radius without throwing in a couple of jugs of diesel in the truck between September and April...but that's just me.

I'd suspect the OP is looking at a summer trip, so the cold weather won't be a factor; and in 2018, between MT and Beaver Creek (my last full-length trip), we never had a problem finding diesel or gas.

To answer the question...no. Sensible suggestions to run off the top half of the tank, to fill up whenever you otherwise stop, and to carry Canadian cash, but I don't believe you need to carry jugs.

...assuming the trip is allowed next year....

You plan you big trips like me, far.... in advance.
My truck is the same as your’s except a 2017, and it has a pretty big tank. I no longer pull a 5th wheel with this truck ( 35ft Open Range) as I now have a camper.
However after I figured out my fuel range pulling the 5th wheel and or the camper I didn’t worry about fuel range ever again, I just keep one of my eye balls on that gauge.
Like pigman1 says, always fill the top 1/2 of your fuel tank, especially in northern BC and the Yukon. When you start driving in the mountains, with long hills, slow curves fuel can gets sucked up fast, as your going to be putting your foot into it more often than on a flat straight hwy road.
As I rule, I never travel more than 2 to 3 hrs without stopping to do a vehicle walk around, and I usually do this when I get fuel. (Kill 2 birds 1 stone) With all the things you can stop and see along the way, you won’t be sitting behind the wheel for long periods of time anyways, I’ll bet.
Also carry enough Canadian cash to pay to fill up your fuel tank. My wife is from Stewart BC ( north western BC) and we have over the years stopped for fuel and found that the debit/credit card machines aren’t always working, for a number of different reasons, so cash was the only way to pay for fuel.
Like others have said Generators are also an issue, however “most” places do have a backup system to keep essential things like fridges, gas pumps etc..running, but ya never know, just like the debit/credit thing.
I will say in out last few trips up north we haven’t run into either of the above issues I just mentioned.
Have fun with your planing.
Soup.

We did the trip in 2019 with a Dodge 2500 pulling a 9,500 lb toy hauler trailer. I added a 30 gallon aux tank in the bed to give me 66 gallons of diesel. We average about 14 mpg when towing.

I spent 3 months in Canada and Alaska and was able to avoid very high diesel prices the entire trip except for 3 fuel stops. Diesel pricing in the US is much cheaper than Canada but with a 25% exchange advantage we averaged approximately $3.75 per gallon in Canada. The three expensive stops were unavoidable because of our route and not driving below 25% in tank.

Enjoy your trip!

Diesel is available, but if you are on the Alaskan Highway stop every time you see a fuel stop & fill up & be ready to pay a VERY high price for it.

Fuel stations can be 100 miles apart, but they will have diesel.

Just ride the upper half of your fuel tank and don't depart a town that has fuel available thinking you'll get some a bit up the road. Roadhouses and stops may get replenished at irregular intervals and many do not have grid power, so a failure of their generator system means no fuel even though tanks are full. We're hoping to make our 10th trip up this summer, Covid permitting.

In general, no. Fuel is available at reasonable intervals, though sometimes pricy. Of course, if you pass by a fuel station without filling up before traversing some broad, sparsely populated areas, that's your problem!

If your truck has a small fuel tank (and so a small range), adding an auxiliary tank may be a good idea, particularly if you are thinking of going to particularly remote regions such as up to Deadhorse on the Dalton Highway. The longest stretch between fuel stops along it is nearly 250 miles.

There are probably more diesel engine trucks on the rural Alaskan and northern Canadian roads than cars and gasoline trucks combined. Diesel is available everywhere.

LeRoy