To expand a bit on the question.

If you had to resort to walking out of an area.

How many miles an hour do you think your group can make and over what kind of ground?
How about in a day or a week?
Are you counting time for feeding and sleeping?
Are you counting the weight of the packs slowing you down?

How about for a person you are looking for after they became lost?

I am like a snail.
_________________________
May set off to explore without any sense of direction or how to return.