Great Wall question

I'll be in China in a couple of weeks for a conference in Shanghai. I was only going to be in Shanghai, but now the timetable for meeting is changed a little bit. I think I'll be able to get up to Beijing, at least for two or three days. I've heard about a section of the wall that is not heavily populated with tourists. But I forgot the name. Is it reachable in a day for time is limited. I have read all the tips about the Great Wall in this forum, but not found the relevant information.
Thanks

Do you mean the Simatai section? Definetely, it is the best official section. Lies 80km northeast of Beijing, Huairou county. Lots of people hike from Jinshanling to Simatai. You can also do it if time permit. There are less people compare to Badaling section. I would give the cautious to take some bottled mineral water from the city. There are no shops on the wall and always some vendors follow you to sell it at a much higher price.

Yes, exactly, I saw it somewhere but I can't remember. Is it possible to camp there. I want to take some pics at sunset and sunrise.

Well, considering the safty of visitors, it is not allowed to camp on the Great Wall now, however, you may stay in a hotel beside. It's quite convenient.

How is the weather?

It is getting cold and windy up there lately, I camped up there in Oct and it was quite cold in the morning. I heard that it is not allowed to camp there any more, but there are guests house at the foot of the wall by Simatai section. It takes 30 minutes hike to the foot of the wall and another 2 hours to reach the 12th tower at the eastern section.

Another section of Mutianyu-the Great Wall is worthy of visiting, few people not crowded.