Is it possible to come to Puzhehei from Yuanyang in a single day by bus? Which is the best route?

Yes, it is possible. The distance is about 186 miles (300km). There is no direct bus. You may take a bus to Kaiyuan (about 2 hours). Then, transfer to a bus to Qiubei (about 3 hours). Afterwards, take a city bus or charter a van/car to the place (about 30 minutes).