With the OP planning their trip for mid October, snorkeling on the North Shore during that time period is NOT a good idea, especially if they are not good swimmers and unfamiliar with the sites.

You might have the occasional flat day out at Shark's Cove at that time, but generally speaking, the conditions at that time of year are not ideal. Hanauma Bay would be a better choice for snorkeling.

I would also recommend only one island, with only one week in Hawaii.

You can try the Big Island, Waikoloa and Mauna Lani. From their finest vacation rentals and services, you can avail it at a very reasonable price. You can have a volcano tour, ziplining and horseback riding aside from water activity of course. I have a friend who visited the place last year and decided to buy a property in Waikoloa. She's in love with the place and plan to stay there for good. You and your family might like it as well for a vacation. Good luck and have a safe and enjoyable trip!

(This thread's a question from over 6 months ago)