I'm planning on traveling around asia this summer and have no idea which country i should start off with.?

Basically, I'm studying abroad in beijing this semester and it's currently summer vacation. I was planning on first going with my friend july 15 to seoul, south korea, the 20th moving to hong kong. after july 23rd i would be free. I was planning on going to other countries including: Vietnam, Laos, Indonesia, Malaysia, Singapore, thailand, Philippines, taiwan, and japan. What do you guys recommend me to do. I really would like to visit all these countries, but i have to be back around aug 20ish to go back to hong kong. Do you know if i should visit any of these countries in october because i get a week off in october