I just installed a set of Recon Big Rig light bars that have the courtesy light feature that you are wanting to achieve with your LED strips. I couldn't find a place to splice into on the passenger side, so I ran the wire up into the engine bay and across the firewall to the driver side, spliced the passenger and driver side wires together, then passed them through a grommet in the firewall into the driver's foot well, right behind the brake pedal. Then snaked them up to the access panel on the left side of the dash (seen when you open the driver's door) and spliced into PIN #13 (dome lights).
Here's a link
to my write up including a few pics showing where my bars are mounted and a video of the bars in action.
This helpful post
illustrates the access panel I previously mentioned and the pin location for the dome light wire you will need to splice into.
Hope this helps! Have fun, it is certainly worth the effort!