How long we took for having a walk on the Great Wall? It is impossible just around 5 days?

Athirah, many sections of the walls are disconnected and they are usually a bit far from the downtown areas. So I am afraid that you may not hike on the wall for five days unless you hire a guide and a car to help you finish your hiking.

I personally think that you might pick up some sections like Badaling, Mutianyu, Simatai and Jinshanling and then visit them section by section. Since they are far from the city, you need spend more than half a day to visit each section.