We did ours last year on our new 2014. I bought a semi-dark plexiglass, measured the door precisely with the radius for the top piece, then the small middle piece and the large bottom. I took the said measurements to our local plexiglass dealer along with a templet for the radius and said here ya go. 2 days later and $48 everything was cut to my specification - precisely.
The doors have a 3/16" thick gap/groove in them so I added the extra length/width to my measurements so I was able to slide the plexiglass into the groove so there is no need for brackets. It just slides in easily and is dark enough so no one can see in yet we can have the main door open. Keep the a/c in and the heat out.
Our second project was to put small (black out) plexiglass pieces in our bedroom. These go on the windows for our slide out where you lay your head. These windows are your typical small ones. We velcro'd them to the inside of the frame, which are covered by the curtains. You cannot see out and cannot see in. These are very private. These work great when your at a camprground spot and your near a spot light or at NASCAR event and near the spot lights.
As soon as we get our camper back from the dealer (another story within RV.net) I will try to post photo's.
Keep the mod's coming as we all like to see what is being done for improvements. Happy Camping everyone and be safe out there.