We spent around 4-5 hours return trip. That said much of the time was spent playing around in the pools and admiring the numerous waterfalls. You could go faster.
You will need to climb around some of the waterfalls using ropes located on the sides of them. Some of the climbs contain sections you REALLY don't want to fall off of. Not suggested if you're scared of heights.
- River Tracing boots - Gloves (the number of ropes you'll be climbing will ruin your hands, trust me).
Really great trace, one of my favourites that I have been able to visit in Northern Taiwan. The water is clean, and the entire area feels quite natural (sans the very start where people hang out). The GPS should take you to a bridge. You will be able to get down and start the trace via a path on the right-hand side of the bridge. In the very first area, it's possible you will run into people. Once you climb the ropes along the side to pass the first waterfall you should have the place almost entirely to yourself. You may run into various waterfalls that seem impassable, there is generally a trail located somewhere around them that will take you up and over them.