I don't think it's necessarily a wiring problem.
Here are my thoughts, having just rebuilt two door lock actuators in one of my vehicles:
First - the rear driver side door sounds like the door lock actuator motor is dead.
Second - the other issues may or may not be related to the actuators. Can you answer this, do the intermittent problems happen only when using the keyfob? i.e. If using the key to lock/unlock works, and the interior manual locks work, and the interior switches work - then you just need a new battery for the fob. Otherwise it may be a door lock actuator - start at the driver's door, as sometimes the others are dependant upon this actuator.
Third - with the locks activating while driving, this could be due to a broken or disconnected rod that connects to the actuator. The door lock actuator is usually connected to some rods/cables that run to the interior and exterior handles and locks. If one of these rods comes out of place, as your driving it may be bouncing around causing the lock to trigger (it thinks the key is being turned or the interior manual lock is being switched). Again, I would look first at the driver's door for this one, but the front passenger's door might also do this. The rear doors don't usually have provisions to lock the other doors, and the wording of your original question made me thinkg it was all the doors that would lock/unlock while driving.
I would start by pulling off the door panels and just looking at the door lock actuators. Is there a rod or cable hanging loose? Trace the rods/cables back - is everything connected at the other end? If so, then it may be a wiring issue.
While you have the panels off, try the interior switches, exterior (key) lock (have a partner do this while you look at each door), and interior manual locks for each door. Does the actuator move with all these events? If not the actuator motor is probably bad.
Do some research online - you may be able to replace just the motor for less than $20. You may have to replace the whole actuator at around ≈$120±20.
To have a shop replace the door lock actuator, probably 2-3hrs billable at ≈$100/hr plus parts, so probably somewhere around $320-420/door.