How can I go to chengdu from hk/ shenzhen?

It will be cheaper if you come from Shenzhen. The flight takes about 2.5-3 hours and ticket fare is around CNY1,000 recently. The train takes about 40 hours and is not recommended.

2 days are just enough for sightseeing in the city itself. For the surrounding areas like Mt. Qingcheng, Dujiangyan, and Giant Buddha, it's not enough.