At the trailhead take advantage of the trailhead bathroom; change into dry clothes; do one last gear check to make sure all the hats, gloves, snowshoes, etc. that left the car actually returned to the car; separate gear into bins in the back of the car that can be transported easily back into the house.
Have a bin for gloves and hats, snow clothes, base layers that need to be washed, water bottles, toys or activity props, etc. You'll lessen the stress and chaos and it will be a lot easier to organize upon your return.
In the car a snowshoe adventure will take a lot of energy so many kids will use the car ride home to sleep. However, if they're still excited from the adventure, use the car ride as an opportunity to debrief. Discuss the best parts of the day, why they were interesting, new things everyone learned, etc. Then talk about where you could go snowshoeing next or what you would do differently.
At home after unloading, make a note of some of the things you forgot to bring that would have been handy. Place the note with your snowshoeing gear or add it to a snowshoe check-off list so that the next time you pack up to go out, you'll remember.