Myself and the wife will be breaking up the long journey to Cambodia by stopping in Beijing, where we will take advantage of the 72 hour TWOV. We don't want to rush and see tons of things, but given the small amount of time, I want to plan this intelligently. The only "musts" for us are The Great Wall at Mutianyu, The Forbidden City, and food. We will be there during xmas time in winter.

Monday - Arrive at 17:55 - Eat Dinner and Sleep
Tuesday - ???
Wednesday - ??? - Depart for Siem Reap at 18:45

My big doubt is when to hire the driver? I read earlier in the thread where someone recommended to combine the GW with the flight departure to take advantage of the driver. But will this allow proper time to get to Mutianyu, enjoy the GW without rushing, and get back to the airport with proper time (2-3 hours early) for a 18:45 departure? And further complicating this is the weather in December. So should we give the wall its own day and maybe use the driver to combine it with something else on the way if we have time? Or should we combine the Wall with our departure flight? Thanks.