Which line is better between Qingdao, Penglai, Yantai and Dalian?

Of course, Qingdao first.

Qingdao, Laoshan, Zhanqiao, Little Qingdao, Zhongshan Park, Lu Xun Park, Naval Museum, Underwater World (if you have not been to Underwater World, you have never been to Qingdao), No. 1 Bathing Beach, Badaguan, May Fourth Square , Olympic Sailing Center, Qingdao Polar Ocean World. Taitung Business District, Hong Kong Middle Road Business District. Zhongshan Road business district. Huangdao, Golden Beach, Silver Beach.

Qingdao can stay at Haier Intercontinental Hotel, Shangri-La Hotel, Regent Hotel, Huiquan Dynasty Hotel, and Yizhong Crowne Plaza Hotel.

Take the high-speed rail from Qingdao to Yantai (Qing-Rong High-speed Railway), visit Yantai and then Penglai, Penglai Pavilion, Penglai Underwater World.

Yantai-Dalian, there are boats every day , if you find it too slow, you can make a plane.