I use to bring all kinds of crap along with me. I have dialed it way back over the years. My tool kit now fits in a bag about the size of a normal shaving / overnight bag (5x8x2).
I have a ratcheting screw driver with the bits stored in the handle, including the common torx sizes.
3/8 ratchet, with one extension, and about 7-8 sockets.
Set of small common size wrenches.
Extending mirror, and extending magnet.
Multi Tool
Zip ties (GOOD, cold weather)
Some folded up rags to clean your hands with
Thats It!
The best thing you can do is go over your sled and just see what you would need to do things like adjust your track tension, tighten a loose shock or suspension mounting bolt, adjust the Toe-in, tight a ski bolt, tighten your handle bars. Just common stuff that might come loose and would be a quick easy fix if you had the correct tools with you.