Which area of the great wall is more practical to visit with limited time in Beijing?

I have a 20 hour layover in Beijing. I will arrive at 18:10 and leave the next day at 15.35. As I arrive later in the day I can't book a layover tour. However, would it be easier to find a hotel near the Dongzhimen Bus Station take the bus to Mutianyu Great Wall in the morning and then leave from the wall to the airport via taxi or metro? If so, how long would it take me to get to the airport? Or would it be more convient to stay near the Deshengmen Bus Stop and take the bus to Badaling in the morning and try and leave from there via metro or taxi to the Airport?

Thanks in advance for your recommendations