see Place of Refuge - an old Hawaiian village (o’Honaunau), Volcanoes Park, definetely go to the South Point, find the green sand beach, Puna Luu is the beach to see too, there’s a thermal pond not far from Hilo

My wife was the same age when we were there and she really enjoyed the Body Glove Snorkel Tour

Its a beautiful Island, Volcanoes National Park is a must, the drive from Kona is spectacular, and you can get right up to the Lava, the hot stuff that is, Hilo is also well worth a visit the Tsunami Museam there is a must. There are some superb Waterfalls en route as well, so get a good guide book. In the other direction we took an evening tour up to mauna kea to watch the sunset and see all the observatories open, that is one trip i would do again and again, they beauty is indescribable if a little chilly, it was so strange to be walking through snow.

There is so much to see and do that it would take much more than this to describe.. you will love it

Let me answer your questions about where to go and what beaches to hit by referring you to a very good travel book. It is called “The Big Island Revealed”. A very candid book that includes reviews of restaurants, descriptions of beaches and their locations and lots of other stuff. I was looking at the recent 4th edition yesterday. As much as I am on the island the book offers insight to a lot of what I do not see.

You can get it on-line (Amazon) or at places such as Borders or Barnes & Noble. Those I have referred to the book who used it gave it a 5 star rating.