For packages and Mail from Europe you can use the office address and send her this template:
ECCS Office Mail Address:
c/o ECCS, Dr. Matthias Niedenfuehr, Beijing 100871 Peking University Dep. of Philosophy, 4th Yard, ECCS, People’s Republic of China
There is always someone reliable at the Zhexuexi to receive you package and it is more safe then your mailbox at the apartments.
For mail you can check the ECCS-Postbox at Zhexuexi after a week or so. For packages plan 2 weeks for airmail or 2-3 months for land and sea transport, SAL (Sea, Air, Land) something in the middle. After that time ask the janitor, Mr. Jia (Jia shifu 贾师傅) whether any packages arrived. In any case the package can take a long time if caught at customs. In such case, usually the ECCS will be informed.