There is no substitute for boots on the ground. Though when I say that, I am less concerned about exploring every nook and cranny than I am about getting familiar with the area and making sure there are no showstopper issues for hunting there. On more than one occasion, I have seen nice looking spots on google earth, only to find out with boots on the ground that the road in got deactivated (or bridge washed out, or gates closed, or otherwise inaccessible) 10 miles before the spot, or the sat photos are a few years old and what looked like scrubby re-gen in some nice clear cuts is now tall enough you can't see 10 feet, and so-on.