Ross: NAC are good. I flew there 2 years ago this coming Sept, and will definately return if I'm in the locality.
It will be hot & probably hazy but should not be too humid. I'm a UK PPL so they just did me an hours FAA BFR & let me lose solo. RT took a little getting used to but most ATCOs were brilliant, especially if you put on your best British Airways accent! Dont hesitate to ask them to repeat - my biggest problem was recognising my call sign - they do it differently; often droping the N and first few numbers, and sometimes prefixing type i.e. a Cessna N1234Z can be 34Z or Cessna 34Z or N34Z, etc....
In contrast to the UK where most ATCs are pleased to "release" you ASAP, "Miami Center" (in effect a RAS) would not let go of me till I was almost on finals back at Naples.
Email Nikki Gentill at NAC if you have any doubts about the new visa requirements - she or her husband will be able to advise.
Enjoy
Ian