how do you remove the rear rotors ?

Once the wheel and brake caliper is removed there is only the set screw holding the disc onto the bearing hub. I would guess rust is just holding the disc in place. Autozone have some popular workshop manuals for free on line once you register (for free) on their website http://bit.ly/autozone_repair_info. There is also a company that independent auto repair shops buy their information from that the same information inexpensively to do it yourselfers. The information is year make and model specific repair procedures, service bulletins, component locations, wiring diagrams ect.... Alldata is very easy to navigate http://bit.ly/AllData_Repair_Manuals_Online