We booked about 4ish weeks after flights were released for our travel dates, so we booked mid-November for travel the following mid-September. Prices were the lowest when we booked, and we only saw them go up from there but we weren't closely watching.
We flew from Buffalo to Atlanta to Honolulu, which made the long haul leg about 9 hours. The flight we chose was very comfortable, so we found it tolerable. Where is your home airport? I know some of the Newark and JFK nonstop flights can be 11+ hours, which might be too long for some people. If you aren't worried about that, I would say its safer to book the nonstop to avoid potential delays, missed connections, and lost luggage.