What is the easiert way to get from Badaling Great wall to the Yiheyuan?

It is hard to avoid going back to city proper if you have plans for Yiheyuan.
A fast and comfortable method is suggested. Take a S-train from Badaling to Beijing North Railway Station. Then walk to the Xizhimen Subway Station to take the subway line 4 to reach Beigongmen Station and then get out of the station to reach your destination.

Thank you.
Do you know which S train.Is it the one from Yanqing ?
I found that schedule for S trains leaving Yanqing at 10:3,11:04,11:34 and 12:46,etc.
If this is the one,the schedule does not say when it departs Badaling. Do you know?
How long should this "s" train take ?
How close id the walk to the Xizhimen station?
How long do you think I should allow for the entire trip?
Thank you very much.

Is there a closer stop to transfer between the 2 sites?

Yes, you are right. The S-trains are from Yanqing, via Badaling.

There are more trains than you listed. I think you can search in the Train Section on this website. You can fill the two stations' name in the searching tool, I am sure you will find what you want. The time shown on the website is the departure time and you need to reach the station early.

The train journey from Badaling to North Train Station is around 1 hour an 20 minutes. Get out of the north train station, you can find the subway station of Xizhimen Subway Station. The subway journey from Xizhimen to Beigongmen costs around 30 minutes, so in total, it takes around two hours from Badaling to your final destination.

Thank you. Do you know if I can get to my final destination faster by getting off at Nankou station?
Where is this station at? Which subway line? There are sooo many.
How would I transfer from there?
Thank you.