Ok, now I see what you mean.
From the link above, you'll find my photograph of how I did install an inverter under the passenger seat of the Venza, including on how to route the cable under the door. Well in fact, the whole explanation is here:
http://www.toyotanation.com/forum/showthread.php?t=310980. More of the same, but when installing the trailer hitch is here (routing wire on the driver side):
http://www.toyotanation.com/forum/showthread.php?t=310856.
Are you trying to turn on the led of only 1 foot well when only 1 door is openned, or lighting the 4 foot well at the same time when any of the door is openned is ok?
I ask because I don't know where to get that wire exactly (what color). But if you look at the first link above, you'll see that I installed the inverter under the passenger seat. I had to route a wire from under the glove box (where you obviously have access since you installed a set of led there) under the carpet, under the door and then under the passenger seat. There are already 3 wire harness going from under the carped to under the seat: I would guess: A) weight sensor for the airbag, B) seat belt sensor, C) pre-tensionner for the headrest. And those don't get damaged by the the rear passenger foot, so I guess if you use the same path with the same wire lenght (and maybe tie-wrap your wire to Toyota's) you can be pretty confidendent that it will not get damaged.
Does that make sense?
jf