Yes, the tourist bus no.6 is only available on Saturday, Sunday and official public holidays. The journey is about one hour. I suggest you take bus no.936 from Dongzhimen to Mutianyu. The bus ticket only costs CNY 6 by using public transportation card. When you get to Huairou, you can hire a private car which costs about CNY 25 and arrive in Mutianyu Great Wall. There are many private cars, so don't worry. It's quite easy to find the cars to Mutianyu. But remember to bargain at a good price.

Hi Sophie,

Thanks for your information. I have managed to book a private car for whole day (CNY 550) to Mutianyu, Huairou villages and Farmer's house for lunch.

Do you think that I would be able to see the autumn colour leaves if I go to Mutianyu on 3rd week of Sep?

From mid of October to the third week of November is the best time to see the autumn colour leaves. I'm not sure whether the leaves will turn its color on 3rd week of Sep in this year.