I'm going to go against the grain but I'd go for the river or canal. You know them so you'll have to decide.
Reasons being, he might feel less self concious when not surrounded by others, he might already have an idea about fishing being something of an escape into the wild. I know lots of people will disagree with me but he also might find the whole idea of a commercial fishery so utterly depressing that he leaves his tackle and walks off to find something more interesting to look at outside. I'm not sure that every one craves instant riches,it might be that he or his son want to share an experience that is rewarding, inetresting and varied.
Which ever you decide I hope they find what they are looking for, good luck.