I did similar, I think?...
I tapped in to the door sill lights and grounded at the door pin switch for the puddle lights and reflector lights
Also if you get interested, It's pretty easy to do foot board lights and under the door cards... I tapped into the illuminated hazard light button and used any grounding points I can find.
(crappy cell phone pictures, but it lights up all the pedals [and it's not quite dark outside so light is still shining through the 4 garage windows])
