Hey the search function will answer most of your questions in detail.
Naples for me was just fine. I spent 7 wks and did PPL/night/imc and left with about 80hrs. Only thing I would do again and strongly advise you to do is finish the PPL written exams before you go there. As My first weeks were spent studying when I should have been flying,so get them done. Really nice area to fly with busy airfields if you want that and of course real quiet spots.
I just loved Pahokee and immokalee /arcadia / la belle/ and of course a trip up to st.pete and Tampa and over to orlando and titusivlle where I went to see space kennedy centre. I just loved it there, Naples itself is a real nice field which can get real busy with bizjets which keeps you on your toes.Accomodation is mainly the Wellsley INN or one or two other accomodations they have but they all need bicyles to get there which you will end up sawing the b0%%0cks of yourself which is a common complaint. If you there for more then 4wks you be better going to the pawn shop and buy yourself a second hand bike for $50 as compared to rent it off naples for $70.
Visas took very little time, you have the advantage that you can walk into the US embassy down at Merrion which helps alot.Certainly no longer then a week or two from the time you get the ball rolling with naples,they send so forms to you etc etc thats the waiting then you only need a day with the embassy,cant remeber how much 70euro maybe???
All in all I spent about 6 or 7000euro which covered all flight /food/accomodation and all the flying. I was issued with a caa PPL and no it needed no conversation what so ever other then the obligatory club checkout. I reall envy you going there, I loved it and some musts are the above fields plus everglades/marathon.venice/page and Ft Myers just north of you to practice ils approaches all free of course or head to Marco island just south to scare the alligators. Ask away