Hi COR4VETTE -
It can be very easy - if the parts are not corroded, and I doubt your 2004 is very corroded.....
Jack the car up ans support it (using a lift or jack and jackstands)
Remove the rear wheel / tires
Remove the parking brake cable from the parking brake actuator lever on each side (probably can be done by hand - mine were easily removed by hand)
Use a breaker bar and a 21mm socket to remove the two caliper mounting-bracket bolts (these are torqued to 160 ft-lbs, so they require a man-sized turn of the wrench, mine came off fine).
Support the rotor and caliper assembly that you should now have in your hands by fashioning a hook from a metal coat hanger wire or tie it up with string etc, just keep it from dangling by the brake line - not good....
I used a 3lb sledge to tap the rotor face in the areas between the lugs, be careful not to impact any of the lugs and bung up your threads.
Grab the rotor with both hands and pull while turning back and forth. It should come right off. If it does not, then try more tapping on the face.
If it is still stuck, then you might have a problem with the emergency brake shoes, which ride in a drum integrated into the rear rotor. I have read some real horror stories about that being a problem, but I have never experienced it myself.
Best Regards -
mqqn