We took a hike straight down Wall Street in Zion National Park last year. It is also called The Narrows. This was a moderately strenuous hike for us. First, because we were not in the best shape. But also because one has to walk in the Virgin River. The stones in the river are very slippery, and it takes a lot of concentration and effort to stay upright!
It was a five-hour round-trip for us. Fortunately, we made this hike in the dry season. Don't go when there is rain anywhere in the vicinity. (Rain many miles away can cause the river to overflow and flood causing death or serious casualties.) Also, head out early if you go in the Summer. Beat the crowds!
woo the view is amazing!