This is not just a route. The thread also has detailed advice on how to take trains and ship your bike back to Taipei as well as inside information on great, inexpensive places to stay.
This ride has it all. Swimming in mountain rivers, hot springs, the ocean, a few climbs (nothing major), lovely scenery of the Rift Valley, and lots of indigenous villages. Enjoy.
I think the thread does a good job of pointing our visitor in the right direction and helping him avoid making newbie errors such as riding on the west coast, Highway 9, and through Hualien City (he looks like he's going to ignore us on that one though).