Winter might not affect all the sates in the union, but in the northern most states and Canada, Winter is a reality for 4-5 months of the year. If your vehicle breaks down on a remote stretch and for some reason you need to relocate - being able to carry all the gear you want or need may be hard to accomplish.
One way is for you to have a backpack/daypack/rucksack to assemble what you need and move on but having an ICE Fishing Sled in your trunk can make a world of difference.
This molded polyethylene sled can play many rolls in your day to day activities as well.
It can double as a trunk organizer, beach gear carry all, snow sled and it can be outfitted with an elastic cover and tow bar. Carrying a small child might exhaust you in short order but being able to slide them along with you to safety can now be accomplished.
It can also be the foundation of a shelter or sleeping quarters for young children. They come in various sizes as you will see from the link below and will fit in SUV's and most mid sized and even smaller cars. These were made to be towed behind snow machines, ATV's or by hand.
We would recommend you place DOT strip reflective stickers on the sides and back. They come with a tow rope installed but you might consider having a front and rear rope to facilitate a two person operation that has more control.
About $25 in Gander Mountain/Bass Pro/Cabela's