Hang Múa is normally known for its caves. I didn't find anything special in it. The 500 step climb to the pagoda is much better.
I rented a bicycle at Tam Coc and cycled to this place. There is a parking lot outside the entrance. They charge you 5,000 VND for parking. Please cross check whether you can park your cycle inside for free.
The entrance fee is 100,000 VND. You can see the pagoda on the peak as soon as you enter.