when is the last airport bus? They run until the last plane...?

In another thread someone mentioned that offerring a tip of ten kuai also solves the problem

wait till the 5th of June, speed should be better then

At university level most if not all Chinese students are able to speak Putonghua, but in Yunnan even in university campuses you are more likely to hear dialect being used unless you are in a discussion with a student.

If you are coming to China for a short term and only to improve your Chinese then I suggest you spend your time in Beijing. Not only are text books based on the way Chinese is spoken in Beijing you will also find that the way people speak to each other is much closer to the Chinese taught in class than in Yunnan.

Hearing Mandarin on the streets helps to reinforce and adds to what you learn in class.

Cities like Tianjin, Xian and even Shanghai are better for hearing Mandarin on the street than Kunming.

On the other hand if you just want to concentrate on learning Chinese in a class or tutor type situation then the ability of your teacher is more important than your language enviroment.

I know its a different direction,,,,but have you tried biking the old road to Songming? no trucks and well sealed roads (cause no trucks) also nice scenery through Bai Yi.

Nice day trip