For what it's worth, I have the following R/T booked for this summer:
IAD-CDG-FRA-SIN (OPEN JAW) BKK-HKG-NRT-SFO-IAD.
23 hr connections in CDG & HKG. 4 day stopover in NRT.
Booked in C to SIN & F on the way home for 130k UA miles total.
I originally booked this on the phone with CO premerger.