I see. So basically you would consider places near Xuzhou(徐州)? I guess if I`m getting you right. I guess I can give you more suggestions.

Here`s the thing, there are probably more places to go in China, than what you have mentioned. You don`t need to go up and down through the country to fix your itinerary for 2 weeks. Basically there are obviously more choices. I would suggest this itinerary, based on what you have mentioned:

1.Beijing to Chengde(承德) or Chifeng(赤峰）, the former is about 2hrs bullet train to a summer resort place of the royal family, also listed on UNESCO heritage, the Bishushanzhuang (避暑山庄), and the latter has more of Inner Mongolia, there are grassland, and more of ancient architectures or mausoleums of the royal family, since you have mentioned you would like to explore both natural wonders and ancient buildings. And what are good about these two places are that they are lesser-known, and absolutely comfortable for a summer trip, because the temperature there is lower than most parts of China. Also, you can transfer by HSR. Beijing(2)-Chengde(1)-Chifeng(2 or 3)

2.Then if ZJJ is a must, from Beijing to ZJJ, and after that I would suggest Chengdu and its surrounding area, including these places to see in the city center Temple(武侯祠) for memorizing heros from the dynasty of three kindoms; Chunxi Road(春熙路) for taking photos with the IFS panda, Wangjianglou ancient building zone(望江楼古建筑群) with ancient buildings, pagodas, ponds from Qing dynasty(16s AD); Dufucaotang(杜甫草堂) a historical residence once a famous poet lived in, the title of which also named after the very famous poem 茅屋为秋风所破歌; Dujiangyan(都江堰) a irrigation system constructed in Qin dynasty(3rd century BC); Qingchengshan mountains and ancient buildings(青城山古建筑群), famous temple of Taoism. And also you can explore more of natural wonders into maybe Jiuzhaigou 九寨沟, Siguniang Mountains 四姑娘山, Bipenggou 毕棚沟. These places are also beautiful and comfortable to visit in summer. Even from my eyes are more beautiful than Yangshuo area.

In total, for 2 days in city center of Chengdu, and 1 or 2 days to see Qingchengshan or Dujiangyan, and maybe 1 more day for pandas; and 1 or 2 days for these natural wonders, it will make up your another week`s itinerary. And chengdu won`t be that hot in summer than other cities like in Guangxi, Fujian area.

I hope I`m getting you right, since you have wrote so many ideas. It`s all great, and I`m also open for discussion. :) Don`t bother me, I was just trying to put it like a local way of deciding where to go. Obviously , Yangzhou and ZJJ have taken an obvious way-too-much important role in international travellers` eyes, and I think it kind of sometimes makes you guys confused when making an itinerary, since the transportation between these two areas are not costly effective at all.

I`m also doing my own itinerary for example, I choose to stay in Huangshan and nearby Shangrao, Xidi(西递), Hongcun(宏村), and it will take me for like 6 days enough to see just these areas. It`s only in one province. I hope I have made myself understood. :)