T.F.
This question is posted often... I still stand by everything I have said regarding discounters...
I never, ever use a discounter because the people who do use it are the first to get bumped, etc when things happen.
You have no support at the airport to help you work through the issues, you are at the mercy of an 800 #. We travel a LOT, I book airfares weekly, and I have seen may people very upset and buying new full fare tickets because it is the only way they can get home. Like the old saying... you get what you pay for.
That said... I only work with the specific airline websites. You can get good deals directly from the airlines. You need to book at least 21 days in advance, more if you know your timing for certain.
I use Southwest and American a lot. I fly hubby to Houston from Dallas monthly for less than $120 just because I go get the deal in advance. I would think you could get a fair deal from CA to Hawaii. Check the specific websites for web specials, etc and you'll end up better off in the long run.
Have fun!