The first time I spotted a cobra (or something that had a hood that pop out when threatened) was in Hualien, in a path near the beach. It was CNY, but the weather was awesome. I was riding my bike and the animal was overcome with some uncontrollable rage and tried to bite us xD
Then the second time it was in road number 7, that goes from Sanxia to Yilan, more or less. We were crossing the mountain, and there were woods everywhere. The animal seemed to be quite pacific, which is the behaviour I´d expect from a cobra, but when I approached it, it showed the hood, but it didn't even bother to confront me. Well, sorry, this was the first time.
The third time was in Yilan, in some road going uphill to some golf camp. My gf spotted it on the side of the road, and I could see it only partially. The animal was huge.
As for the caolin, gaolin, kaolin, whatever trail, it´s this one:
taiwanderful.net/guides/caol ... oric-trail
It´s located in the north east coast, and it goes from Fulong to Gongliao, more or less.
However, if you´re looking for snakes, I´d recommend you to go by night to YMS and check the sides of the road. I´m sure that there must be snakes there. I even saw some people "snake seeing" or something in Wanli by night. They were checking the sides of the road with flashlights. If you ever do that, I would like to join, specially if you are experienced with these animals. I used to love them, and now... I´m just scared of them
PS: here in Taiwan there's at least one more snake with hood besides the cobra. They look similar, not sure if they're easy to tell apart...