Kauai vacation

Hi, we are planning a week in Kauai. I'd love to find a place to stay that I can swim in the ocean right nearby that is not too expensive. Also as a lake/ pool swimmer anything special to know about ocean swimming (I'm a strong swimmer but live land locked).

Any tips for mountan biking?

Any must dos? We want to kayak the coast but are still putting together other ideas (we just found frequent flyer tickets).