BUS FROM GUIYANG TO ANSHUN TO GUIYANG

Hi,
Can someone help me or any advices are welcome.

I want to visit the Huangguoshu Waterfall and the Dragon Palace Cave Scenic Spot. I plan to stay in Guiyang city. I plan to take a bus from GY to Anshun early in the morning.
a. Can I make it in a day to visit these two places and return to GY after the visit?
b. What is the last bus from Anshun to GY or what other transportation is available?