I did my entire car PC install without any visible modification to the car. It can be changed back to stock in less then an hour.
I did the same thing with the car PC on my Mazda Protege, literally I looked at the PT cruiser at 8am...went home converted the entire car back to stock, and went back at 9am to trade it for the PT.
That cubby hole will pop out with taking apart the rest of the dash.
There are snap-tabs on the left and right hand parts of it, grip the inside and just pull.
You can get to the wires that run to the power plugs behind there. But it's not that easy, as they are typically wrapped in tape most of the way.
What I would do is run two new wires from Connector 104, wrap the wires as you go around an existing bundle of wires (So you don't have slack hanging down into your pedals.
This thread has some info on connector 104:
http://www.ptcruiserlinks.com/forum/...searchid=20527
The Red w/ White wire (Pin23) is the always on center console outlet wire
The Pink w/ Red wire (Pin 22) is the switched main console outlet wire.
I recommend buying a service manual online, I bought mine here:
2006 CHRYSLER PT CRUISER CAR WORKSHOP SERVICE MANUAL - Documents / PDF
It is over 7000 pages long, but the PDF makes it navigatable via point and click. The manual has built in guides on how to read their schematic, and where the connectors and such are located in the car.