well there would be a lot easier place to tap into.....that is if you want the lights on all the time, and that would be the AUX power (cig lighters). as they are only powered up when the car is on....so as soon as you shut off the car and start to open the door it will go off. Just like like your radio does.
as far as the ABL wires.....it all depends on when your car was made. the early to mid 2010s had a connection on both sides that nothing is connected to, we believe it was originally for the dash abl that GM decided to delete....later models the wiring harrness were changed so its not there. BUT if its there, the connection that is easiest to get at is on the left side, just pop off the fuse panel. in this thread, in the first two posts there are good pictures of the connections you were asking about asnd how to access them.