This serpentine trail must be from a mouse. The other, shallower marks in the next photo branch off from the mouse trail and I'm not sure what to make of them.
This one shows the mouse trail crossing the "freeway" of back-and-forth tracks of a larger animal crossing our property and going into the woods behind the old grange next door:
The last five images show what I think must be woodchuck tracks; we have one around here, we've seen him several times; though a friend says these look like possum tracks, and I hear there are possums in these woods. You can easily see how the claws are dragged backhand, forward, then the paw is placed down in front. Really interesting tracks. Click on the images for a better view.