EWR-BKK is a valid idea. I plan to do it myself. Note that you can also go EWR-SIN. Actually, any NW flight to Asia will earn you CO mileage. Also consider KUL via KIX on NW. It more milage if you go thru the West Coast. On NW, the tickets seem to be about $850 RT. They tend to be more expensive on CO, but you can buy a NW ticket on a CO codeshare and fly on a CO plane to NRT. However, the layover at NRT is long, about 5 hours Westbound, less Eastbound. It may be worht it if you can upgrade to Business First. Note that upgrades are most easily available on Tuesday or Wednesday on NW or CO.