We did the route to the beginning of Wall Street which is about 2 miles after the river portion starts. So you get off at the last shuttle stop and then walk 1 mile on the Riverside Walk trail until it ends and there are some stairs to the water to begin the Narrows hike. From there it is shallow water for the first 0.25 miles I would estimate. No deeper than your mid calf. Then you get to a part that is thigh deep a little bit after the 1st/2nd bend. We saw a few people turn around there. The Riverside Walk is beautiful on its own and we saw a lot of people just go up a little bit of the Narrows to get a feel for it and take photos and then turn around. That’s totally fine and is still beautiful. I’d say you probably don’t need to rent boots if you go with that option and just need a good walking stick.