You could consider other comfortable (and expensive) cities in Japan such as Fukuoka, Osaka or Nagoya. However, flights to Japan from SIN can be expensive.

Cheaper destinations... Vietnam (Hanoi, Ho Chi Minh), Burma (Yangon) and Cambodia. Not sure about the weather - might be hot and rainy that time of the year.

Your post serves as a reminder for me to plan my own trip from SIN next time I'm home in the Far East!