Beijing Badaling Great Wall & Ski Resort

You are suggested to take subway line 5 at Dengshikou Station, and get off at Yonghegong Station. Then transfer to subway line 2 to Jishuitan Station. And then walk to Deshengmen Station and take bus no. 919 to Badaling Ancient Great Wall Station. After arriving, walk to the scenic area directly. It will take around 1.5 hours on the way. To the ski resort, take public bus no. 919 at Badaling Ancient Great Wall Station, and get off at Xibozi Station. Then there are cars that can take you to the destination. Or you can walk to the ski resort from the station directly. It will take around 30 minutes.
According to your plan, maybe the time is tight. So you can also hire a private car to get to those two places. Or you can join in a one-day tour. These two ways save a lot of time. Have fun!