You sure about wanting to go outside of the USA? Look into passport etc.
Take a look at South Padre Island, TX. You fly into Brownsville, rent a car, 20 minute drive to the beach. There's a buncha nice places to stay there, lotsa decent restaurants and saloons. Great beaches. Plenty of recreational stuff to do like dune buggies, horses, waterpark, parasailing, golf, boat tours, fishing (piers, party boats, charter boats) shopping etc.
Its a real friendly place, and everyone speaks your language
Look at it on the net, I can give you local tips if you're interested (which places are dumps etc).