RE: Ghost bucks
All very good questions but I have to believe that all areas have the potential to hold a big buck. Big bucks do not get that way by being dumb. They adapt to their surroundings. I think a lot of this goes back to the other post you are referring to and the big argument of just because they are there doesn't mean I can get to them.
I think for the most part, the older these deer get, the more they just lay low and come out after dark and feed and get back in before first light. You don't see them because they don't want you to.
Now factor into the picture the RUT and finally you have the a slight advantage. Hell, if you lived in seclusion for 10+ months a year, you'd do dumb things in your pursuit of the ladies.
I guess my short answer is, they hang out on unreachable/inaccessible lands and eventually wander out in search of necessities (food, water, ladies, etc.)