PDX MSP or DTW are typically better options to get to NRT than SFO SEA or LAX (really long nonrev lists)
I frequently monitor past flt skeds to both NRT and BKK legs

Keep in mind you can now connect thru Haneda and layover then head to NRT as well. We've done ICN but then it's not DL metal (we used skymiles for biz class) but it's a funky place to hang for a day

I'm going to BKK next month w/buddy pass rider via SFO for her--I haven't decided which works best for me yet, since I have so many options.
more to follow...

GOOD GRIEF--this is an OLD thread!!