Depending on how long the honeymoon will be, it may be worthwhile to consider using a travel certificate. With this, you could fly to Hawai'i using airline miles and spend a week in your preferred hotel. If you have 10 days, you could split the 7+3 and make full use of the 7 nights of the certificate.

Hapuna Beach is one of the nicest beaches on the islands and certainly #1 on Big Island. However, there is next to nothing going on in the area, so you would have to cover some distance to get to Kona.

The Wailea Marriott is a very nice property and the area offers more for travellers that seek to leave the hotel every now and then. And if you don't want to stay at the pool, you can easily head to nearby (small) beaches.