Red Beach in Panjin, Liaoning, if you are alone, you can consider local groups, but you must go early. If you are with some friends, you'd better rent a car.
Mudanjiang Jingbo Lake? Many people recommend this place, but I don't think it has anything special, but I will list it for you and decide for myself.
Huanren Wunv Mountain &; Around Longhu Lake, you can stay at Huanren Hotel (run by the county government) when you get there. Then join a local tour group, which is more economical and simple (there is a good travel agency around the corner outside the passenger station, where you can sign up for rafting in Daya Bay).
Dandong? There are many mountains in Dandong, but unfortunately I haven't been there. You can check it online, including Phoenix Mountain, Qingshangou and Wulong Mountain Scenic Resort Scenic Area.
Dalian, the Binhai Road in Dalian is well worth hiking. In addition, there are many good scenic spots in Lushun District of Dalian. Such as Bai Yushan, the natural boundary between the Yellow Sea and Bohai Sea, Japanese-Russian prisons, etc. The Golden Stone Beach in Dalian is also good, but Lushun is in the south of Dalian and Golden Stone Beach is in the north of Dalian.
The easternmost part of China-the earliest place to watch the sunrise-Wusu Town in Fuyuan is close to Wusuli River, with good ecological protection.
I have never heard of the Seven Lotus Ponds in Harbin mentioned upstairs, and I have heard of the Five Lotus Ponds in Bei 'an. I haven't been there, but I hear it's good.