I have a 2014 and just swapped my mirrors out for the tow mirrors, took about 30 minutes total for both doors.
1. 3 bolts in the bottom of the bottom of the door
2. little access panel in the door handle, pop that and 1 bolt.
3. 1 bolt behind the plastic cover for the door opener.
4. 3 nuts holding the mirrors on and one electrical connector.
5. I left all the wiring on the door and my dad held the panel while I removed and replaced the sideview mirrors with the tow mirrors,
I was impressed on how smooth it went. The link below will basically show you the hidden bolts.
How to remove interior door panels. 09+ - Ford F150 Forum - Community of Ford Truck Fans