To see Guangzhou, Guilin in 6 days cheaply and back to Hong Kong

To be honest, the best way from Guangzhou to Guilin is by air. You can also take train, but it takes a long time, about 12 hours. From Guangzhou to Hong Kong, you can take train from Guangzhou East Railway Station to Hung Hom Railway Station, Hong Kong. For a cheaper way, you can take train from Guangzhou to Shenzhen Railway Station, then walk to pass through Luohu Border, you will get into Hong Kong. Then you could take the East Rail Line to downtown area of Kowloon.