We've only done the trip once, but we flew from Buffalo to Honolulu with a layover in Atlanta. Our flight from Atlanta to Honolulu (and vice versa) was roughly 8 hours. We opted to go with Delta because they have a slew of amenities for coach class to help pass the time comfortably, and also because the flight times were ideal. We left Buffalo around 6am, 2 hour layover in Atlanta, arrived in Honolulu around 2:30pm local time. On the way home, we left Hawaii at 4:30pm local time, two hour layover in Atlanta, and were home in Buffalo by 10am the next day if I recall.
When arriving in Hawaii, it did take us about 2 days to adjust to the time difference which caused is to wake up very early those days. We knew this would happen going in, so we took advantage of that by doing Pearl Harbor and Diamond Head those mornings because those are best done early in the morning. On the way home, we didn't sleep much on the overnight flight so when we got home, we forced ourselves to stay awake until our normal bedtime. By doing that, we didn't have a hard time re-adjusting back home.