Gold Panning Las Vegas

How can I tell by looking at a mountain that it might contain gold in it?

I drive from Las Vegas to Prescott Valley often, and I see many hills and mountains along the way and I would like to some day stop and pan for gold in one of the many dry creeks that stream down all these mountains, but which one should I look for?

If there was an easy way, don’t you think that it would have been used and that all the gold would have been panned and picked out already?