So wife and I are saving up our miles for a business class trip. Would like to head back to Asia in a few years ^ Almost there, figure another 90K or so. So here goes, we were wondering if this itinerary was possible and if not any suggestions? Trying to get as much for our bang as we can and see Japan, Malaysia, Thailand and fly back home via Singapore.

DTW-NRT
NRT-BKK
SIN-DTW

Any comments? Thanks in advance, as always you guys know it all when it comes to miles/points.