This is a classic northern Taiwan overnight ride. Just 130km but 3,500 meters of cumulative elevation gain. Try this one after you have done the Northern Cross and are used to climbing in Taiwan. The climbs in Hsinchu County are some of the steepest in Taiwan but the ones on this ride are moderate by Hsinchu standards if you do the ride in this direction.
Road bikes are fine on this one.
We stayed in Luona (羅那) just before the climb up to Yulao. There is supposedly a guesthouse in Luona, but when we called from the road they were full. So we asked at a traditional grocery store and were soon directed to the home of a lovely elderly Atayal couple who put us up for the night and served us Atayal warrior soup (Taiwan Black Pig pork with pigeon peas).
Here's the elevation profile and map. We had great weather this time (early October) but the pass up to Yulao is often cold and wet in the winter and spring.