After reading through ALL of the comments above (instead of the first 4 or 5) I installed libimobiledeviceutils and in a terminal found that "idevicepair pair" then allowed successful mounting. Subsequent umount/unplug then automounted when plugged back in. Seems that the utils may need to "pair" the device before it will work properly.
After reading through ALL of the comments above (instead of the first 4 or 5) I installed libimobiledevic eutils and in a terminal found that "idevicepair pair" then allowed successful mounting. Subsequent umount/unplug then automounted when plugged back in. Seems that the utils may need to "pair" the device before it will work properly.