What we know:
1. Chad is a hicker
2. Chad have a property somewhere in the aera
3. At least two of the photos were taken in a private property.
4. There are a lot of nice places to hike at the West of Chad's location, and not too far (I calculate it in a diameter 2 miles away from Chad's location, in a straight line) which is VERY easy for someone who use to hike.
5. These places have lots of houses that haven't been explored by Frank and Tom; and i will surely not blame them for that, the place is really hard to explore with all these little roads, paths and houses everywhere.
6. The place where Chad's wife cellphone photo was taken is the highest place all around the aera: if one want see something above the valley, it's THE place.
7. The only way to join this place by hiking is by the private dirty road:

8. We are sure that all these photos were NOT taken the same days and that there's two sequences:
- The cellphone photo (n°1)
- The others (n°2 to 6 [the "sky" one]
Then, to resume, my points are:Chad lives somewhere at the West of where the photos were taken, in the valley. He saw the drone most of the time from his house, and sometimes outside, hiking alone or with his one month pregant wife.
(We can hiking with a one month pregant woman, I have done it myself with my wife many times, and for miles.)
He knows that the only way to photograph the drone properly is to get the place where is wife firstly took the cellphone photo and also that THE ONLY WAY to get it is by the private dirty road.
Firstly, he went to this high place with his wife for a walk (and maybe for admire the view) passing by this private road that he knows very well, since he's a neighbor (and maybe a friend of the owner), his wife took the picture with the cellphone and, SINCE THIS MOMENT, Chad knows that if he want to see the drone again and capture it, he have to get the summit.
Then, secondly, he returned to the summit another day with his friend and neighbour, here again, by the private dirty road, to try to see the drone again and took the rest of the pictures, beginning with the "Valley" one (n°2) almost at the same place as his wife and him saw it for the first time. The drone coming at this time closer, he didn't hesitate (and remember that he probably knows the owners of the privates) to go on a private road to get better shoots.