You need an expensive, well located accomodation with a direct beach/ocean view - called oceanfront. Also, because of her limitations, I'd get a jeep or 4wheel drive that will take you some backroad areas that are unusual-road to Hana and so forth. You could hit Oahu for two nights(Sheraton Moana), like Dawn said-spend the day at Pearl Harbor and perhaps the evening at the Polynesian cultural center. Fly to the Big Island(Hawaii) the next day for four or five nights including a helicopter flightseeing over Haleakula(the only way to see it imho!) while choosing a wonderful room at Mauna Kea, Kona Village, Mauna Lani or a two bedroom condo
on the ocean south of Kailua-Kona. Jeep around the island one day and discover it on your own. See the Kohala coast where the Kamehamehas ruled. Then, off to Maui for six/seven nights and a wonderful condo either in Wailea or north in Kapalua that has ocean views. Find a
travel agent who can guarantee you oceanfront because in Hawaii, 'ocean view' means if you hold onto your wife's belt and she leans as far off the balcony as possible...you get the idea. Seriously, you can do this
right or you can do it
cheap and rarely do the twain meet in Hawaii anymore. Sadly, the days of that happening are pretty much gone. We used to stay at this little B&B up in Kapalua on Maui-wonderful breakfast on the beach; the accomodations were pretty much a thatched hut with a very comfortable bed and a tiny little pool. mmmmmmmm, the memories. Classic Hawaii has some pretty good information on their website regarding accomodations. The flight is very long. You spend a day going and a day returning. I've planned many Hawaii trips and taken several. April can be rainy so I'm warning you off Kauai as it's very rainy to begin with. I had a client insist on Kauai in April for her 10 day honeymoon; it rained all day, everyday - hard.