distance from no 78 dongsi jiutiao dongcheng to great wall and best (most challenging hike)

Sean, the most challenging section is Jiankou (Arrow Nock). But it's too dangerous. Some people even lost their lives when they tried to hike there. I personally suggest that you may hike on Simatai or Jinshanling section. Jinshanling part is about 130 kilometers from Beijing city. Simatai is about 167 kilometers from the city.

Thanks so much Sally...which do you prefer, Simatai or Jinshanling and why...also I've read you can hike from one to the other, but can it be done in 1 day?
Thanks again for all of your help on this.
Sean

Sean, I personally prefer to visit Simatai because it still keeps the original appearance. And I am afraid that you can not hike between these two sections. You know, Simatai section was reopened. Guards petrol on the wall to stop people hiking.