How long approximately would it take to walk the 500 kilometers of the Beijing Great wall.?

I am not very clear but I can give you an example. It is about 10km from Jinshanling to Simatai part and it need 5 hours' hiking. However, the wall is not through all the way. I mean some part is broken and can not go through on the wall, but need a deture to the hill foot and get then get back on. Some part are not open to the public now, such as Simatai.