I have already used Google Earth for G.C. trails. You can see the entirety of the N. Kaibab trail , the S. Kaibab Trail, most of the River Trail and Bright Angel Trail. Also the Clear Creek Trail and the Tonto in the Corridor area and beyond.

The trails show up better than the stupid red lines now that are supposed to show the trails but don't quite.

I've actually used a screen shot of the intersection of the N. Kaibab and Ribbon Falls trail to give to someone who had been there before with me but wanted something to have "just in case".

Of course, this may actually be helpful where there is tree cover and you can't actually see the photo of the trail itself. . . .