Have any idea which island you'd like to visit?
Seems to me, personally, that Kauai is the most beautiful and one of the least visited so less crowds. It's also the wettest meaning it's the most luscious! The northern Napali Coast is absolutely breathtaking. There is one particular hiking trail (Kalalau) along it that's spectacular!
You guys seem like you're into hiking

I've always wanted to visit Hawaii Volcanoes National Park on the Big Island. It looks incredible!
Interisland flights are pretty cheap, around $80-90USD. Best way to see any island is by car and cars get booked really fast around the last two weeks of December.
Ahh, I'm having nice warm thoughts now
