How do I get to Mutianyu if we are staying at Red Wall Forbidden City Hotel?

You can go to Dongzhimen and take bus 916. Get off at Huairou International Conference Center (also Mingzhu Square) and take a local bus to Mutianyu Great Wall. A lot of private buses or taxies will take you to the wall. But remember to bargain a good price.

Around Huairou, you can take the famous rainbow trout, baked or raw. People would also try the authentic "village food" there, very fresh and tasty. Xiangshui Lake is worth visiting if you have more time in Mutianyu Great Wall.