I went a little different with this install... All of the "truck bed lights" I could find had 60 inch light strips, which was about double of what I needed. Some of those can be cut to length, but I liked the preassembled waterproof kits. I actually used this underglow kit. It came with 2 - 3 ft strips and 2 - 4 ft strips.
These probably aren't as bright as some of the one color white bed lights.
Installation
I tied in to the eDIY plug on the right, drilled a small hole in the D-pillar for the switch. From there, I drilled a hole in the top of the cubby and mounted the controller / IR receiver in the top of it.
I used a fish tape to run a cable from the side drainage hole in the front right of the bed, all the way back to the cubby hole.
I mounted the 4 way splitter on the back of the Retrax canister.
I mounted the 2 - 4 ft LED strips across the back/bottom of the Retrax canister. Mounting them on the bottom would probably put off more light, but wanted them protected from cargo.
I mounted the 2 - 3 ft LED strips on the bottom of the Retrax side rails.
I used a ton of these to wrangle and secure cables.