Just returned from HNL->FUK(HA 454)->NRT->PEK->DAL->FUK->HNL with a few new observations (please read if not interested in FUK):

Unexpectedly, HA 454 was almost full when going back to HNL, while DL 598 did not seem to have that many passengers (I observed Delta boarding on two consecutive nights). On HA 454, I counted 30% empty seats on the way out (Mar 6), but only very few open seats when returning (Mar 21). Business/First was full both ways! I randomly sampled passengers and found 70% were Japanese visiting Hawaii, followed by Kamaaina with ancestral ties to Fukuoka going there for the first time. There were only 3 "haoles". Unlike the Kamaaina I interviewed, my sample of Japanese passengers was not aware that HA 454 is planned to be discontinued in June, so this was not the reason for their booking.

Moondog mentioned that Air China would have trouble to fill flights between FUK and PEK, and so they would have a stop in Dalian (CA 953). I talked to the flight crew of CA 953, and the reason given for stopping in Dalian was: There is a large Japanese population in Dalian, with many of them traveling back and forth between Fukuoka and China! And the Dalian->FUK portion of CA 953 was full, while the PEK->FUK portion was only 60% full. But I second Moondog: There is not enough demand for a flight between PEK and FUK to make it worthwhile for HA to route their PEK service through FUK should they choose to do so. But there might be an unexpected pocket of Japanese in Dalian that could be interesting as a target.

While in Fukuoka I spoke to a small sample of Korean tourists to sample the idea of a combined HNL->ICN->FUK->HNL service (just a crazy idea of mine). The idea of combining a hot spring vacation in Kyushu with a beach vacation in Hawaii was received extremely well by some of the more wealthy couples from Seoul. So this might be a better option than HNL->PEK->FUK->HNL.

Demand generation: When in San Francisco on March 3-4, I did spot several large HA posters with the message, "Hawaiian Airlines: Proud sponsor of the Embarcadero Ice Rink". If this kind of demand generation had been done in FUK, then I think that HA 454 would have had a much better chance (especially since DL did not do any of this in Kyushu).

Just my 2 cents.