Depends on YOU really. I did mine in 3 weeks but I wouldn't recommend it for everyone. I had about 2 years previous to going to Florida clocked up about 20 hours but for various reasons didn't finish. So thinking that the only way I was going to get through it was to get onto an intensive course free of weather delays etc Florida it was!!
Now think of a typical day. Up at 6-7am, bit of brekkie and perhaps study, then get to school. Brief with instructor, check plane, fuel, weather, fly for an hour or 2. Land, refuel, befrief. THEN hit books, eat lunch whilst studying, brief with instructor, fly for an hour or 2. etc etc. Go home with the other students to the shared accomodation at say 6pm, grab a bite to eat. Hit the books, get to bed hopefully before midnight or when you find yourself not retaining anything more or your eyelids drooping. Next morning it all starts over again.
That would be an average day for the entire 3 weeks. Obviously as soon as you can start knocking off the ground exams a bit of the pressure will be removed. Of course that then gets thrown back on you with things like your first solo, cross country planning and of course the skill test.
Had a ball though it had to be said. And it was quite nice sitting out in the sun studying in Florida working on my tan. If I was you though I would try and knock off the exams before you go so that you can just "enjoy" the flying which don't forget is one of the reasons why you are doing it in the first place.
PM me if you want any more details.
PS: Before anyone else says it, don't expect to have any time to do sightseeing although you might find you need 1 day aviation free just to relax!!