Your friend is probably talking about the Canton Fair - the time when hotel rates triple in Guangzhou.... Best way to go would be by direct train - departure is from Hung Hom Station. From past experiences I'd suggest to get the tickets well in advance. I am not that updated about the hotel situation there, but the China Hotel is one of the closest to the exhibition center. The Garden Hotel as well as the Holiday Inn and the Guangdong International (they changed the name of that one frequently, it is opposite the Garden Hotel) are not too far away either. Not sure about the Dang Fang Hotel (opposite the exhibition center) - back when I was living in Guangzhou is was in desperate need for renovation. The other option would be to make it a day trip and return back to Hong Kong in the evening.