Rotors are wicked easy to change, after putting the car on jacks, it should take no more than 30 mins to change them. The wheels hold the rotors on, once you remove the wheel and caliper (two bolts), the rotor should just pull right off. There is a small retainer clip on one of the studs, but that is just there to hold the rotor in place while you put teh wheel back on. You can pull that clip off and throw it away, you don't need it. The only time you would need to pound the rotor off is if it is rusted to the hub. A few bangs from a rubber mallet should do the trick.
Brake pressure will go down only because you press the calipers back in place. Once you have everything back together, two presses of the brake pedal should return the pressure to normal...car running of course.
As far as brake in period, just don't stomp on the brakes for the first hundred miles or so, other than that nothing needs to be done.