A small but good thermos or insulated water bottle, buried inside the saddlebag so it lasts longer, fill with HOT tap or coffee pot water before leaving the hotel. Good to drink, or to thaw the ice from Bombardier helmet ports. Still wet at the end of a cold day.
1.2mil garbage bag to line your saddlebag, 2 gallon zip lock Freezer bags (those are heavier duty than the storage bags) inside with your dry stuff, don't overstuff, they flatten and pack nice. Never had one open or fail. Couple candy or energy bars, the light airy ones are easier on the teeth when frozen compared to the heavy solid ones. Put one in an inside pocket a half hour before eating. A couple dog treats or jerky for the friendly dogs you meet along the way. Change the belt before the trip if it's remotely used, so your less likely to need your spare, because then you'll have no spare. 5 or 6 foot security chain and good lock for sled-to-sled lockup to make your stuff look less attractive than the unlocked sleds nearby. Thin gloves and gauntlets for comfort and dexterity. Rain-x your shield before the trip to make freezing rain easier to clear off. At least 1 person should have a shovel, folding saw, fuse assortment, big and small ty-wraps and fresh duct tape for MacGuyvering, spare gas for whoever needs it. A volt meter is sometimes handy. Motorcycle compact jumper cables, they always work compared to the wizbang lithium jumper packs that are hit or miss. Flashlight with spare battery. I prefer the Fenix E12 since it's pocket size and takes 1 AA battery which is 2x capacity of AAA and it's the same battery my GPS can use in a pinch. Spare balaclava, sometimes to swap, sometimes to double up on the thin ones when it's -30, with Windblock fabric in the neck is much warmer than airy fleece, yet still thin and not bulky. Some plan in case a heated grip fails. 1 spare carbide. Bonus cinch strap ( not a bungee, they don't work good in the cold) over the saddlebags to prevent bouncing which can easily rip the factory straps out of the bags, eye bolts in the tunnel to attach. A spare strap for "that" guy that didn't plan ahead and now has torn his luggage strap out and it's really flopping around. A motorcycle cargo net is also awesome insurance! I like a combo cable bike lock to lock my jerry and permanent bag to the rear bumper, again just to add a layer of inconvenience to me or thieves. Small Leatherman for cutting belt fragments that wound up behind the primary. Spare fuses, and if Skidoo....spare relays, and know where all of them are ahead of time, on the trail in the dark when it's -30 is no time to dig out the manual. Spare helmet cord for that rare occasion you may need to plug in. Copies or PDF of all your paperwork, passport, and credit cards front and back, email to yourself. Earplugs if you're a light sleeper. Ice scratchers for those few occasional just wrong morning hours where it was groomed like concrete the night before, and it takes a couple hours to loosen up. When stopping, peek under for bent carbides or loose studs, even the pre-studded Studs pull out or can partially pull out and flap into a heat exchanger. Name and email address labels on stuff like keys, phones, bags, gps, etc. Email always works, your phone number may not. Nice to haves include an axe, sat phone, bus schedule. Must haves are a lot of money and a good sense of humor for the inevitabilities Murphy throws your way. That's it for now ;<)