Looking at the flight path of TG 640 (BKK-NRT) of past few days, the flight pretty much passes between Nii-jima (Nii Island) and Miyake-jima (Miyaka Island) before landing at NRT. More closer to Miyake-jima, which is pretty far from Mt. Fuji.
Yes, sit at left side of the aircraft. It has to be clear day to see Mt. Fuji, but my guess is that even if it is clear day Mt. Fuji will be far away and seen pretty small in distance.