It's a bit of a solution in search of a problem; but pushing a laden bicycle 'ho chi min trail' style one can go practically anywhere a man can go.
With a rope to pull it up after the climb one could get over a cliff or wall.
But I'm not sure why you would need to bug out with 400 pounds of equipment unless you are somewhere you won't be rescued for months and i can't think of an example.
The Sock