It's actually not too difficult
Just grab our Bed Lighting System Kit here:
http://www.4x4truckleds.com/2015-ford-f-150-bed-lighting-system-w-baja-designs-s1
This kit includes a single rear BuiltRight Industries Bed Rack Panel (shown in the photo where the shovel is). It can be mounted on the either the driver or passenger side. This photo shows an example of a similar setup, only the light is not the Baja Designs S1 and it's using the larger panel instead of the smaller panel.
We decided to go with the smaller panel so that you can throw light into the whole bed. You could certainly go with a larger panel option if you wanted and aim the light back though.
Just shoot me a PM and we can discuss options/etc...