3
We stayed a Torre del Greco which is a 15 min drive from Pompeii and it still was a day trip, you canspend easiely 4-8 hours in Pompei itself, the japanese trour groups were a lot quicker than we, but I would not do such a long train ride just to pop in and out in an hour.
5
perhaps technically feasible, but not something i would even seriously consider. As Aribo says, even from Rome the usual answer here is not to go to Pompeii as a day trip. You would probably spend 9 or 10 hours in transit, in order to spend, what, 2 hours at Pompeii? sounds like a waste of time and money to me.6
We've a friend here on Ischia who's a registered guide, and much of his living comes from people making daytrips down from Rome to Pompei. Not cheap, hiring him for a whole day - but it gets them his services from the moment they step out of the carriage, all the way to the site, and until they're back to the train home again!However, to arrive at Naples on the same FrecciaRossa that his clients might use (which leaves the capital at 09:00, and gets in at 10:10), would require being at the station in Florence for its 07:00 departure...
In all, your day would be at least 4 hours longer than theirs - and you'd travelling about 1000 kilometres!
Whilst not quite the same spectacle, if you'll be visiting Rome, how about Ostia Antica?
http://www.pbase.com/isolaverde/ost_antic
Peter
Edited by: a_brit_in_ischia

