I want to visit Tsinghua in Peking University tomorrow. Do I need a ticket? How to arrange the route? thank you

You don't need tickets. Take Metro Line 4 to the East Gate of Peking University, enter from the East Gate of Peking University (you may need to register your ID card with the security guard), turn around and come out from the East Gate, and walk north for one stop to the West Gate of Tsinghua, then you can start the tour.

Prepare for a full-day tour, Peking University in the morning and Tsinghua in the afternoon. Lunch can be settled at the place 200 meters north of Tsinghua West Gate, where there is a small street, which is cheap and delicious, and the sanitary conditions are poor. If you want to eat better, you can also go to the food street outside the west gate of Peking University, but it's a little detour.

You can also walk along Chengfu Road from the East Gate to Lanqiying. There is a row of restaurants near Lanqiying, including Sichuan cuisine, Hunan cuisine, Yunnan cuisine and Northeast cuisine. After dinner, you can go a little further to the South Gate of Tsinghua, and enter from the South Gate to start the tour.

You'd better take a map. If you have any questions about the route, you can ask the security guard or the school students.