I would highly recommend Sarasota, Florida. Try the Helmsley Hotel there. It is absolutely fantastic. I think you fly to either Ft Myers or Clearwater airport. It is a quick easy get away and really great.
Also St Thomas in the US Virgin Islands. I dont think you need passports etc since it is property of US.
As someone who moved from Sarasota - Bradenton area to Ft Myers, I recommend Fort Myers, after Jekyll Island Georgia