Ask the driver if he's going on the Chengya Gaosu, that's the highway between CHENGdu and YA'an. "Ni wang chengya gaosu neibian ma?".
Do not try to go to the beginning of G5-road. Havy traffic and no way for cars to stop! Chengdu is the gateway to Tibetan Sichuan. The hitchhiking situation changes completely. Any people take you with them and the cities are small, so you can walk out easy. People may also now the thumb sign again!
Chengdu direction east: [http://cymytrip2.over-blog.de/article-von-chengdu-nach-danba-59020210.html]