It has been 5 years since I made it to Hualian and Taroko so I am going to make it a point to make it there this fall. I just need to make a 3 day weekend to make it worth it because of awful travel logistics from KHH. I guess I was in Hualian overnight on a cycling trip (and 4 years ago) but that doesn't really count since I was not sightseeing.
Just to add onto this two of the top river traces that I know of are the Golden Grotto (Hansioux mentions it) and Nanao/Jinyue over an hour north of Hualian. I have done Nanao before (several years ago) http://theworldisnotthatbig.com/2012/08 ... dventures/
and it was awesome. Golden Grotto is talked about a lot as a great river trace and it is near the top of my list. My understanding is that it is tough to get a permit unless you are there right away in the morning (weekends). 1st come 1st serve each day?
I will also need to check out these others sometime.