First question , How do I access the ignition switch to tap into a wire to it ?
Take a look at the pic below
the lower panel on the dash under the steering column is held in place with clips ,, pop this panel off #4
then you can remove the three screws from the bottom steering column bezel #2,, and then pop off the upper and lower steering column bezels #1 and #2 ,,, then you have access to the ignition switch #6
Second question , How to remove the radio ?
take a look at the pics below
the bezel around the shifter in the console has to be removed , its held in place by clips, start at the rear and work your way back with a flat bladed screw drivers and pry the panel up and out
now open the ash tray and remove the ash tray cup to expose a screw and remove the screw and then pry the a/c control panel bezel away from the dash and remove it
then open the top two a/c vents and pull them out ,, they will pop out ,, then release the tabs on each a/c vent retainer and pull the retainers out to expose two screws behind them ,, remove the two bolts on the bottom of the bezel and then the bezel with the radio will come out
any more info on this , just ask , we can go back and forth on this page
Running the wire from the battery to the amp ,,, first you have to open the hood and take a look at the fire wall, look for rubber boots that wireing harness may go through the fire wall, or rubber plugs in the fire wall,, this will be spots to run a power wire through,, if no access holes are found on the left or right side fire walls then you will have to drill your own hole in the fire wall and add a rubber grommet to it so the wire does not short out ..
in the pic above ,, #1 can be removed first with a flat bladed screw driver ,,, then open the console lid and start at the rear of #2 and pry the bezel up
do you need any more info ???