I've always wondered this but couldn't a park owner / operator simply create their own share-able and free Google Map by simply going to the beginning of each trail and adding a thumb tack with the trail name? Then a trail user could simply open the free map and see all the points on the trail easily. Of course, the actual trails wouldn't be on the Google map but the owner / operator could simply superimpose their hand drawn trails on the printed Google map. I think between GPS and a good printed map it would be very difficult to not know where you were.