Difficulty: Section one is a road, 90% flat. Really easy. Section 2 to Long Ke is about 300 meters climb. I'd say 6/10.
Appreciation: 9/10. The views of the reservoir are quite nice. Long Ke is magnicifent.
Transportation: Better go on a Sunday as the other days make transportation harder. From Diamond Hill MTR station, KMB 96R will take you directly to Tai Mong Tsai Road where you get off on the stop right after Pak Tam Chung stop. Otherwise, you can take bus 92 to Sai Kunk, then 94 to the same stop. Return by backtracking from Long Ke beach and hailing (or calling) at cab at the pavilion at the dam.
Why it's worth it: