Going to Mutianyu from Dongzhimen

Hi,
1/ We saw in our guidebook that we can take a direct bus (867 and 936) number from Dongzhimen to go to the Mutianyu part if we leave around 7am. It doesn't talk about another shuttle or minibus. Do we have to take something else ? Does it stop near the ticket office ?
2/ Bonus question : can we take the cable ride only to go down ? Can we pay at the top of the Wall ?
Thanks !