Totally grueling but amazing! It’s really tricks your mind on the way out- it appears that you’ve only got a couple of outlets to pass (see a pic of the napali coast and then you’ll understand) and then by the time you round the next one, 5 more appear! We camped in one of the caves at the end of the valley for over a week (it was all the food we could bring along) and hiked up in the valley for a while. Fun stuff!