Answered by Emily from USA | Jan. 19, 2018 00:55
To Mutianyu: walk to Wangfujing subway station and take line 1 to Jianguomen, then change to line 2 to Dongzhimen. There you can take bus no. 916 or 916 express to Huairou Beidajie. Another change is needed to no. h23, h24, h35, or h36 to Mutianyu Roundabout. Then walk to the entrance within 3-5min.
To Badaling: walk to Tiananmen West bus stop and take bus no. 5 to Deshengmen. Take bus no. 877 to get there directly.
Both parts are popular. Badaling has more visitors. To avoid crowds, Mutianyu actually is a better idea.