There would only be a rear heater core if there was a rear heater, which I don't believe was an option.
The alternator is mounted down low on the back side of the engine.
You need to support the engine so that the cradle can be removed and the mount can be unbolted and replaced.
Remove the right wheel, then get down underneath it, remove the splash shield, back off the adjuster, remove the belt, and unbolt it.
i found out how to do it.
Follow the instructions on Youtube.
Under the car by the back axle.
Turn the key to the right.
It's on the top back corner of the transmission.
On the top of the transmission housing at the back corner.
In the ceiling housing for the rear A/C.
It's at the top of the transmission on the back corner.
Attached to the back side of the throttle body.