It's about 3 hour drive from PEK to Badaling Great Wall. Start from PEK, take bus no.359 and get off at 东直门外 (out of DongZhiMen), and take bus no.800 (外) and get off at 德胜门西(west of DeShengMen), and take bus no.919(快) and reach Badaling. (You should take 919 (快),the ticket costs CNY 12 and the bus is green color).

Does the busses run on weekends and if so up until what time? Is there any faster way to get there?

Yes, it runs until weekends. The bus no.359 runs from 05:10 to 22:00. The bus no.800(外)runs from 05:30 to 22:00.The bus no,919 runs from 06:30 to 18:30. If you think this way is too complex, you can take the train S2 from Beijing North Railway Station. It runs at 07:26, 09:33, 11:08, 13:19, 15:01 and 19:32. You can buy the ticket at the railway station window. It is the multiple unit train, very comfortable, and the ticket costs CNY 17 for the first class and CNY 14 for the second class. It will take you to Badaling Great Wall also.

Thanks, so If I take the train will I still have to take a bus to get to the wall or does it take me directly there?

The train will stop at Badaling Railway Station, about a ten-minute walk to Badaling Great Wall, there is no need to take a bus. Good trip!