Anything below the yukon line of Canada is cheap for American travelers, hell you might even be able to walk to VC if you live in Seattle
Puerto Rico is another good one, doesn't even require another passport since it's in the US
You could also island hop to Australia or Japan but that takes either a boating friend or boating skills
If all goes to hell (and you want to visit the Netherlands) go to one of the Carribean Dutch holdings where they use Euros and have ol'Dutch style houses