I agree that Aeroplan is a good option for MR points. 75K in business one way.

For UR your options are a bit more limiting. UA really raised the mileage requirement last year so business will cost you 80K with them one way. I don't think there is much use in using BA Avios for such long flights. I'm not sure what KE's award chart looks like but I think they only do round trips.

For Star Alliance typically there are one-stops available IAD-NRT-BKK on ANA connecting to TG or ANA. I think ANA has changed over to flying the latest config 777 on this route all the time now.I think the quickest routing is IAD-PEK-BKK on a combination of UA and TG. But I hate transiting through PEK.

SQ might work as it is a transfer partner of both MR and UR. But they've gotten a bit stingy with their award space at the cheapest levels. But you can't book via their website unless you want to pay for an add on flight since their website won't show partner awards. You also save 15% of the miles required if you book on their site. I flew SIN-FRA-JFK in the suites class for 93500 miles plus $400 in taxes and fees. Then just bought a $70 UA one way JFK-IAD.

The last few years I've been getting to Asia using AA miles on CX via JFK and HKG.