They are all clean and relaxing places. It is easy to find transportation. It is best not to have too few people. Safety is the most important thing. Green Stone Valley, go to the mouth of Benxi, then go towards the water cave, cross the water cave and then to Tanggou, you should be able to reach the Green Stone Valley. The small islands around Dalian are also convenient. Take a train to Dandong, then take a boat or bus for 20 yuan/person.
The weather in Shenyang Island is fine now. It’s a nice place. Choose the latter. There are more people and the environment is also good