Suggestions ?! 30 Days in China, four friends, landing in HK and departing from Beijing

Hi,

Me and 3 of my buddies will be in China from mid-july to mid-august. We are landing in HK and spending a couple of days there and leaving from Beijing. We envisioned Chengdu at around the 14 day mark, and would like to know what cities would make sense to stop by on both the Guangzhou - Chengdu line, as well as the Chendgu - Beijing line.

We're not so much into the big flashy stuff, while we do want to see the classical hits, we're more into nice cities, of smaller sizes. We don't mind missing out on the Terracota warriors for example.

Any China tips, suggestion would be greatly appreciated. We're Canadian, if that's relevant in any way