Need help choosing the best way to reach Sapphire by the end of the year; I'm based in Tokyo and have a JAL Card.

Current status:
Record of 2015
9 flights
(JAL Group：9 flights)
29,310 FLY ON points
(JAL Group：29,310 FLY ON points)

Planned flights so far:
Haneda to Ho Chi Minh City round trip September 4-7 (Dynamic Saver; 4,860 FLY ON Points)

Preferred destinations:
Boston (7,500)
Ho Chi Minh City (4,860)
Singapore (5,768)
Taipei (2,796)

I usually fly Economy Lowest but if I can reach Sapphire quickly with a couple flights, I'll spend the money. What is the best way to get to Sapphire with those destinations in mind?

Thanks!