I put a PT Cruiser (don't you judge me) dome light over the rear seat area in my '08 and wired into the front map lights (the interior is all black and you couldn't see anything back there). I used a straightened out coat hanger to fish the wires from the rear seat to the front lights, found the hot wires for the map lights by poking my test light through the wire's insulation, and when the test light went off when the map lights went off, I knew I had the right wire. I skinned back about 3/4" of the hot and ground wires (didn't cut them) and wrapped the wires from the rear around the skinned places and then taped them. The rear dome light comes on and goes off with the map lights and I've had no problems at all. I wouldn't think your LED's would pull anymore juice than what I did. You could be more professional than me and solder and heat shrink the splices.
My "Pocket Rocket": '05 Silver Metallic Escape XLT, 3.0L V6, 4X4, MAC SRI, custom 2-1/4" catback w/turbo muffler, SCT XCal3 93 octane ECU tune, approx. 240 hp, 4X4 fuse pulled (rice humiliator)
Wife's: '08 SES, Airaid SRI, no resonator, SCT tuned