Babel....
I work very closely with numerous flying schools in the USA that do UK JAA PPL courses...and in the process have met with dozens and dozens (if not hundreds - over the years) of PPL students.
If they are on the rapid three or four week residential courses - for which Florida is famous - they ALL agree that the workload of learning to fly AND doing the ground examinations is an absolute nightmare.
There is little or no social time left if you are at the school all day and then have to sit in your room all evening studying Trevor Tom books...with no one there to explain the stuff you are struggling to understand.
By the end of the three weeks, the students are often exhausted....and very unhappy at the effort they had to put in...NO HOLIDAY IN THE SUNSHINE!!.
Take this a step further....the flight test cannot be done until all the writtens are passed...if you struggle with a subject, for any reason, and cannot get them all done before your flight home, you may not be able to do the skill test in the USA...that would then entail numerous extra hours of flight training in the UK before you are ready to take the test with a UK school, in UK airspace.
Even worse...if you fail one subject three times...you are prohibited from taking the exam again at the school...you have to go to the CAA building in Gatwick. This would be the immediate end of your flying holiday....all a big waste of money.
Go to your local school...get some groundschool....do all the written exams (or as many as you have time for)...try to get the R/T practical done (and then keep to that standard when you fly in the USA).....then come out here and ENJOY your flying holiday!!
It would even (maybe) put you below the 18 hours a week maximum studying time that would require you to have a visa for entry to the USA....doing a 45 hour course over three to four weeks would let you in (legally) on a visa waiver.
Final thing to consider is that, usually, there is little to no genuine groundschool in the USA flight schools. You will be sent home with a copy of Trevor Tom and told to teach yourself - but things like Air Law and Navigation are different on each side of the Atlantic.
DO THEM IN THE UK BEFORE YOU COME OUT.
(e-mail if you want to talk further!!).
Enjoy the flying....and with the pressure off...you could probably do the night qualification at no extra cost.