From eastern USA to Guam CO has the fastest service through Honolulu on flight 1 from IAH. There is an aircraft change in HNL though the flight number is the same. Its two 8 hour flights through HNL vs. 1 13.5hr flight IAH-Narita plus 3.5 hour flight on 737 with domestic first seats Narita to Guam, so you save several hours through Honolulu vs. Narita and also I think you arrive more refreshed doing 2 flights of equal length rather than 1 very long flight and 1 short one with potentially domestic F seats.

For going only Tokyo Guam, however there are 2 daily 767 both with BF seats. Very comfy.