If you only play Weihai Yantai, six days is enough.
Yantai is worth recommending Penglai Pavilion Scenic Area and the polar ocean world there, followed by Changyu Wine Culture Museum in Yantai City. Moushi Manor, located in the north of Qixia City, is the largest feudal landlord manor in the north of China, with the most complete preservation and typical characteristics in China. If you have seen a similar classical courtyard before, it's almost the same.
Yantai can stay for about three days.
Then go to Weihai. Also worthy of recommendation are the scenery along Chengshantou, Liu Gongdao and Weihai New Bund, as well as the thriving Korean clothing city. Now that the season is changing, you can find some clothes. You can go to Chengshantou first, stay with local fishermen, eat fresh seafood, get up early in the morning and go fishing with the captain. The air is not generally fresh, and the environment is not generally quiet and comfortable.
It's good to stay in two small cities for three days each, and you can enjoy it slowly if you have leisure. It's ok to take the bus and see the scenery on the slopes of the streets and alleys of the city. At least it's not as hot as Qingdao, and you can take a bath in the sea. The international bathing beach in Weihai City is good, just near the Weihai Campus of Harbin Institute of Technology. Its style is a bit like Qingdao Shilaoren, and its coastline is wide and flat. I haven't been to the Golden Beach in Yantai because it's a little far away. The one in downtown Yantai is really likable.
You may have read my answers in other places. I just went to Jiaodong Peninsula alone. All the references I provided are worth a visit, that's all.
ZDM 888-Level 7 senior manager on the second floor actually copied my idea. Ha ha, ha ha ha ha ha ha, but the answer is irrelevant, wasting my wisdom, stupid!