If you can do rear brake shoes on a Mustang, the cable is easy.
The ebrake cable is secured in the body by a clip at the end near the pulley bracket. The clip can be hard to get out. The brake end requires the use of a big pair of dikes (diagonal cutter pliers) between the ebrake cable spring and the arm to which the cable connects. Once you have the dikes in place, push back on them while holding onto the stamped metal arm. Squeeze the dikes to clamp the cable. The wire is very tough, so don't worry about damaging it. That will free enough of the cable up so that you can slide it off the hook on the stamped arm. Installation requres a pair of vise grips to hold on to the stop on the ebrake cable end and the use the dikes like before. Then you will have enough free cable to slip it into the hook on the arm.