Without looking a girlfriend wants me to install a amp with subs in her 06 without the NAV system. I was just going to tap off the rear speakers for the high level, but need to get behind the radio for the ACC wire.

im confused with your query

Basicly I am going to add an aftermarket amplifier in her trunk to power 2 subs. I will grab the signal from the rear speakers (high pass) and can easily get the power and ground. What I need is the "remote" turnon for the amp. I can go behind the deck or get it from another location. I wanted to see what was all involved in getting to the back of the stereo. Does half the dash need to come out or is there a quick way of doing this?

THis is what u should do: DO NOT USE THE HIGHPASS INPUT! get yourself a LOC... Line out converer... I use Navone Engineering LOC... they are all hand made and are supported fully by David Navone...

For a Remote you can easily just patch it into any accessory that turns on and off with the car... Like the Cig lighter.
I think your best bet is the Cig Lighter
Do not tap into your Fuel Pump fuse only beacause i have blown mine out before on my Dodge Ram... Its just a pain...