Very interesting photos; thank your dad for his service and sharing his photos.
The photos of Hue were very gripping since they were taken soon after the Tet Offensive in January, 1968. That was the ancient capital of Vietnam. One looked like an ancient temple.
If you get the chance to ask your father a little bit more about the photos, maybe you could write a sentence or two telling us more about what's in the photos, like you did with Fort Dix and the West Germany photos. Obviously, some are self-explanatory. It looks like he was on patrol in some of them, and in another something (is it just rubbish?) is on fire.
Whereabouts was LZ English, if he can recall?? So your dad was a U.S. military advisor / trainer for ARVN troops??
Someone mentioned Esso. I live in the U.S and haven't heard of it. Gas stations tend to operate here on a regional level. Is that a European gas (petrol) company??