Where's the leak???

I have a 2004 Ford Explorer that has a coolant leak on the back side of the engine. The intake is dry so I don't think I have a cracked intake & none of my freeze plugs have fluid present around them. I have 1 main wet area around the rear corner of the passenger side head which leads me to believe that it is a leaking head gasket but the truck isn't running hot. Any ideas??