On the drivers side of the truck there is a cable that runs along the frame from the pedal, then is split to go to the two rear wheels.
I also agree, this is usually the sign that you need new parking brake shoes. A common failure for old shoes is for the pad to separate from the base, which would result in no parking brake.
The pro to this is that the rotor will come off much easier if the pads have failed. If you plan to do the job yourself, buy all the hardware also and replace that as well, you don't want to have to go back in there.
When I did the ball joints and wheel bearing I also changed the rotors. I had to use a large gear puller to get the old rear rotors off. There was a good rust ridge from the parking brake holding it all together and the puller was the only way to force them off, even with the cables completely slacked.
