I'm in a similar boat. I ended up just going with a dash light that is suctioned to the windshield and nothing in back. I was able to tuck the wire under the dash without removing anything. I will tell you, if you really slam the pedal down, and have an iPhone 6 in the slot below the screen, it can actually fly out and hit the switch on the plug, turning on the blue light. It is repeatable, but not recommended (unless the call is a fully involved structure fire at your residence, of course!).
Also, if you ever need to leave them running on scene to prevent getting creamed you need to leave the fob in the car, put it in neutral and engage the parking break. Sort of a pain, and it does turn off eventually.
If you want to hard wire you should be able to pop off the nosecone and get access to the low voltage battery. I didn't want to put holes in things, so didn't go that direction.
[video]https://youtu.be/e3r3DRVWzSQ[/video]