Hi Jonas,
Firstly I'll make it clear that I didn't do my PPL with Naples, my PPL was done here in the UK five years ago. What I did do atin NAC though is the FAA CPL/IR.
As razzele says the airspace is conducive to efficient flight training. The practice area seems to be to the south over the shoreline, around west abeam Marco Island. This is only 8-10nm south of Naples airport. No other controlled airspace except Fort Myres Class C to the north (around 20nm north) and Naples own Class D. There are a couple of Victor Airways but they are Class E and no clearance is necessary if VFR which you will be when you're doing your PPL.
NAC charge aircraft hire / instructor time by the hobbs meter, so as soon as you start the engine to shutdown you'll be paying. However the times in your logbook are when you start taxiing to brakes on (stop taxiing after landing). This works out around .1 extra on the hobbs than time in your logbook each flight.
Air Traffic Delays... None with the exception of a minute or two when waiting for IFR release with Fort Myres Departure (but you'll be VFR). Two runways. Taxi times vary, but average around 1 minute for R23, 2-3 minutes for all other runways. Took the Arrow IV up on my own to practice some landings the day before my CPL flight test, taxi'd to R05, called ready for departure and Tower asked me to taxi all the way back to the other end (where I came from) as the wind was now favouring R23... (I saw it change nearly 180 degrees whilst doing my power checks).
Whilst I was there the PPL students were all pretty young (most in the 20's but one 16 year old). Nearly every single one of them were obtaining their JAA *and* FAA PPL's within the 45 hours. One of them passed his checkride with 39 hours so had to burn another 6 hours off (did the FAA bits in the process) If not then 50 hours would have seen them finish. So the 45 hours were including 5 hours at night as well.
One thing to note... ground school is charged at $35 per hour including briefings / debriefings (before and after flights). But its only going to be a little $5 or so extra per flight.
I spent around $20-$30 per day on day to day living. BUT this was with evening meals at the nice restaurants in Naples!!! I stayed at the Wellesley Inn which as it was in their off season (July) was only $33 per night including tax.
I'm going to NAC next March for the FAA Multi Engine Add-On to the CPL/IR (and will probably also do the JAA Multi flight test as well), when are you thinking of going?
Best wishes,
Charlie Zulu.