I'm with quiltmau, on Oahu, see the Punch Bowl National Cemetery and Arizona Memorial. Be sure to see it at the National Park. That way you get the boat ride TO the memorial and get to go on it. Then go to another island, Maui is gorgeous, very green and lush. You can go to the top of Haleakala and bicycle down, if you like. Hawaii Island is almost another planet and sooooo much to see. Hawaii Volcanoes National Park, takes a couple days to see it. You can see the lava flow into the sea, at night, if you want to do the walk.
Place of Refuge,
Pu`uhonua O Honaunau National Historical Park, is a beautiful park. Tells of the Hawaiian culture. It's between Kona and HVNP. In Captain Cook, there is a MARVELOUS fabric shop, H. Kimura is the name. The Hawaiian prints are astounding. There is also a small quilt shop in Volcano Village (the village is near the entrance to HVNP). Hilo is also interesting, farmer's markets, small shops, restaurants. Pahoa has some interesting places too. Just to drive around the island is a continual site to see.
Been to HI twice, but only fly in and out of Oahu. Way to many people and always a traffic jam waiting to happen. But if you have to stay there, go out of the big city to see the real thing. Next time I want to see Kaua`i and Moloka`i. Have fun, just be sure you buy fabric, there is nothing like it. Makes perfect souvenirs for yourself, lays flat to pack. But if you find too much, may want to mail it back. LOL!