Young honeymoon

The problems I see arising are booking hotels and rental cars which should still have an age limit. You'll also need a credit card. Maybe a travel agent can help you? You can also go local for your honeymoon, drive your own vehicle, and go camping. It sounds very different from what you wrote, but just an alternative that others have done. Really, you can honeymoon anywhere in any way you want. By the way, so you can financially prepare for next year, a honeymoon in HI may cost $2-5k, bungalows over water in Fiji (only place I know) may be up to $8k depending on flights. Best wishes

There are tons of places that have overwater bungalows: Bora Bora, Fiji, Maldives, Belize, Mexico, Vietnam, Switzerland, Panama. They are all over the Caribbean. There are even some at the Disney World resort in Florida.

I suggest Sandals. My partner and I went to Royal Plantation in Jamaica. It was gorgeous and so much fun! There are other resorts that have lodging over water. It's expensive, but I think the price is worth it for what you get. LM raised a good point about rentals, but Sandals takes care of everything for you so you don't have to worry.