In the last day or two there have been several deals on airfare to Hawaii that are well below the normal price for these routes. What often happens is that airlines attack each other’s hubs with low prices. When this starts a short-lived airfare war, you can win if you act quickly. As always, the best/easiest source for this info is by following @theflightdeal. None of these Hawaii deals have been lasting very long, but the ones I know of that are currently working are from Charlotte or Phoenix to Honolulu on Delta for about $384 round trip.
The “See Calendar of Lowest Fares” function on ITA Matrix can be helpful in spotting the cheapest dates. You cannot book via that site, but it can be helpful in hunting down the dates you want to go after on a site you can book from such as Delta.com in this case.
If you want one of these trips, I would act quickly. You don’t really get better prices to Hawaii from those destinations (especially the East Coast), and at that rate using cash or fixed value points would be a better deal than miles.