Great Wall during february, any recommendations?

I am going to Beijing in February after the Chinese New Years with three friends. We arrive at around 5 pm and have four days from this point. We all want to see the Great Wall and two of them want to see when the Great Wall meets the sea. How can I plan this the best way when we also want to Mutianyu section, because it's the most child-friendly section, also easiest to hike because of the cold weather in February?