You indicated in your initial post that you were willing to go to different islands provided it would be easy to get back to HNL. The major Hawaiian islands all have easy flights back to HNL. If the St. Regis Kauai is not of interest to you, you should consider either the Four Seasons Hualalai on the Island of Hawaii (aka The Big Island), it is a really nice resort that is close to the airport, but doesn't really have a beach. You could also consider the Halekulani in Honolulu if you wanted to be in HNL. My personal favorite hotel in the Hawaiian islands is the Manu Kea but it's not quite luxury compared to the Four Seasons, although it has an amazing beach.