This video explains the flushing process very well:http://www.youtube.com/watch?v=Lnu8hA9F9S4
Use real AC flush, FJC makes a good one called Kwik Klean. I did the entire system with a quart, and a flush gun. The undercar lines are almost impossible to flush unless you take them off the car. The condenser is parallel flow, so it can't be flushed. I wouldn't flush the hose with the muffler on it, do so at your own risk. The muffler is empty, but crap could still get stuck in there. Removing the spare tire tub is a must, just for much easier access and getting to the fitting above the steering column shaft.
That whole DVD is the best thing Autozone ever sold, and it looks like most of it is on youtube now.