In the log file you attached you only go into AUTO twice. For 1 second and again for 7 seconds. During the 7 second run I can see the servo output trying to steer your Rover so it looks like its working.
You have SPEED_TURN_GAIN set to 1. That means it will apply 1% of CRUISE_THROTTLE (which you have set to 50%) when turning a corner and you have SPEED_TURN_DIST set to 2 meters away from the waypoint. Put SPEED_TURN_GAIN back to 100 and try again.
Your FS_THR_VALUE is 980 however your RC3_MIN value is 900. This means when your throttle is at minimum on your transmitter (I assume you have calibrated the transmitter as the min and max values have changed) your Rover will be in constant failsafe mode and as you have FS_ACTION set to 2 (the default) it will always go into HOLD mode. Lower FS_THR_VALUE to less then 900 - try 850.
Let us know how you go.