Do be realistic! When back in your home country for a short break or even for a longish period, you will probably find little time for language study. So focus on simply maintaining your present level in Chinese rather than planning to study lots of new material. If you are able to accomplish this, you will have done very well!
Here are a few simple ideas:
Chat with Chinese friends using Wechat.
Write emails in Chinese to Chinese friends.
Read a chapter from your favorite book each day.
Read online newspapers in Chinese.
Read/Listen to: http://chinesepod.com
Listen to lectures/talks on Youtube.
Take the recordings of textbooks you have studied and listen to them while traveling. If you must take textbooks home, take just one. However, let’s be honest, you will probably never even open it!
If there are Chinese students studying at a university near where you are living, offer to exchange English for Chinese.
Audit a Chinese course at a local university.