if i were you i'll choose to use NH and SQ on a routing something like this

IAD-JFK UA
JFK-NRT NH
NRT-SIN SQ
SIN-BKK
BKK-SIN SQ (take the earliest flight out then you'll have roughly 20 hours in SIN)
SIN-NRT SQ (take a stop over in NRT and enjoy japan for however many days)
NRT-JFK NH
JFK-IAD UA

All this would still cost 90k a person BC. you can experience Raffles class spacebed, New Style Club ANA, and UA first class..all in one ticket ^