Are there any cheap and safe guest houses or hotels near Xinhua College of Sun Yat-sen University or in Tianhe District?

There is a "Huamei Guest House" opposite the Guangzhou campus. It costs 50 yuan a night and the equipment is still good. If you want something more upscale, you can take a bus (all 6 bus lines in front of the school are available) to Longdong, where there are four-star hotels. As for the Dongguan campus, I haven’t been there yet so I don’t know the details.