Going off the beaten track isn't really that hard in Hong Kong. Actually, that's true for pretty much every city and country in existence. But what I mean here is that public transportation is so good that it's really not so hard to get anywhere in Hong Kong. So while most people don't head out to see the Ten Thousand Buddhas Monastery, it's easy to get to and worth the time.
The monastery is open 9:00-5:30 every day, and admission is free. Plan to spend a good bit of time here, both for the journey up and down the hill and to take time to explore the grounds. And extra time for the Po Fook Ancestral Halls.