Last Trip from Jinshaling/Miyun County to Beijing (city)

Hi, I would just like to ask what is the last trip of the bus coming from Miyun County back to Beijing (city)?
We are thinking to stay at the wall until 7pm after sunset then go down from the wall, eat dinner then go back to the city at 8:30 pm. Maybe we'll be at the city at 11:30 pm if it's 3 hrs travel. Is this possible? ;-)

Hoping someone would reply. Many thanks!