Denis,

Sure that degree of detail is necessary. As a teacher, I learned long ago not to be too sure about what people know. You'd be surprised how many don't know that "went" is the past tense of "go" especially. I find that precision in teaching helps the beginner immeasurably.

As for the POV, yeah...problem - but I find it's often the case when you attend to writing and logic details, it often corrects those problems or at the very least makes them much more easy to spot. Do you think it's easier or harder to spot a POV problem in lean, well-constructed, logical writing or cluttered, poorly constructed, illogical writing?

Details are of prime importance. Take a look at what she thinks is a "much wider" part of the "river" - 30 feet. That means the rest of the "river" is much less than 30 feet wide. That's called a "creek" where I come from. All through that piece are errors in detail like that. Clean those kind of logic details and the writing details, and she'll be well on her way to a good story.