Guangzhou is the third largest city in China.
Hitching out: West towards Nanning.
There is a toll gate at 22.747377,108.271414 which is easy enough to get to and is good for getting a ride. Use Google Maps to find the metro and bus routes to take. Once there, a sign is useful because the spot is also an unofficial long distance bus stop and people will presume you're flagging a bus if just thumbing. We'd recommend only trying to get to Yunfu from this spot which will get you to the first petrol station on the toll way and from there, you can petrol station hop all the way to Nanning. Once we got a sign to Yunfu sorted, we got picked up within 10 minutes.
We camped right next to the toll gate in a little triangle shaped park. It has comfortable grass, and no one much cares. Just be careful of "landmines."