D.B.
If you're in the East, realize that you will spend a full day traveling out to Hawaii and a full day back. And yes, it's expensive - not just the flights, but the food/entertainment.
If it were me, I'd go to something tropical in the same time zone (give or take one) - friends of mine just went to an all inclusive place in Cancun (they took the kids but there were tons of restaurants on site, snorkeling, visiting the Mayan ruins, etc.). They found it on Expedia or Travelocity, I forget which. The US VIrgin Islands and Puerto Rico are US lands so it's awfully easy to get in and out, and everything is available in English at least as one option. Puerto Rico has beautiful beaches, the only rainforest in the US territories, historic old San Juan, phosphorescent waters (take a glass-bottom boat tour at night), and much more. These are great escapes, and you can get there in 3-4 hours or so.
Look on the usual travel sites, but if you're a AAA member, don't forget they have a free travel agency and great ratings of hotels all over the place. You'll know exactly what you're getting.