Am I on the right path?

IMHO you aare giving Rome short shrift - it really needs 3 full days ata a minimum (4 nights). And you really don;t need to bounce around The Amalfi area so much - it;s so small you can stay inone place and just do trips by ferry or bus. As for going from Sorrento back to Rome - I would do either train or bus (which I beleive is direct) rather than fooling around with a ferry and then having to trek through Naples toget to the train station.

I'm tired just reading this. If this is a once-in-a-lifetime trip, then MAYBE I would try this. If I were going on the trip, I'd select just one region, base in that region and do only what I could do in day trips. Ditto the nytraveler advice on Rome. 3-4 days there is really the minimum you will want to get a good sense for all Rome has to offer.

Your entire Tuscany/Florence/Pisa/CT/Siena itinerary doesn't make sense. Neither does all the hydrofoil trips.

If your first destination is Sorrento, you would take the Curreri shuttle bus from the airport to Sorrento (10€) instead of taking a bus to the Naples port, a hydrofoil to Sorrento, a bus from Sorrento port up to Sorrento. The shuttle bus from the airport will run more often than a hydrofoil.

To avoid backtracking and wasting time, you can either:

1. Put Rome at the end of your trip (since that is your departure city). Train from Naples to Florence (visit Florence), train to CT (either briefly stop in Pisa on the way or pick up car and visit on way to Tuscany), visit Tuscany (including Siena and spa), train to Rome (turn car in at Siena,Chiusi,Orviet or any of a number of places in southern Tuscany) for your last 4 nights (yes, you need four if you haven't been before).

2. Visit Rome upon leaving Naples/Amalfi area, train to Florence (need more than 1 night IMHO), train to CT, pick up car and head to Tuscany/spa. Turn car in at airport when departing.

If this is your first trip to Italy, I agree that you need to slow down, organize, consolidate, chill. Fly into Naples, go to Sorrento for 4 days with day trips, go to Tuscany for a few days using a car for day trips, return the car to Orvieto, train to Rome for a few days and fly out of Rome. Save CT for another trip - one coastal destinations is plenty for this trip.

Once you have decided on a more reasonable itinerary, Fodors folks can help with the details. As it is, your current plan is pretty impractical as well as exhausting! You won't remember anything but public transportation.

This might help others understand your proposed itinerary more clearly;

SORRENTO - 2 (hydrofoil from Naples) (day trip to Capri)
POSITANO - 1
SOMEWHERE ELSE AMALFI ??? - 1
ROME - 3
TUSCANY UMBRIA - 4
FLORENCE - 1
CINQUE TERRE - 2/3 (stopping in Pisa)
ARGENTARIO - 1 (stopping in Sienna)
ROME - 1

The first thing I notice is that Rome is split. Why not do it for 4 days at the end of your trip? Spending one day in Argentario then travelling to Rome for the last night before flying home does not make a lot of sense. I would bite the bullet and travel all the way to Tuscany from The Amalfi. I count 16 days minimum, 19 maximum in your available time.

I will make the assumption that you really really want to go to that spa in Argentario. ON that basis, I think you might be stretching yourself to far geographically to have the vacation range from The Amalfi coast to CT and back to Rome. The suggestion to perhaps leave CT off the list makes some sense as you are getting a 5 nights of coastal time already. If that sounds reasonable to you, consider this;

For 16 days;

Sorrento/Positano - 4
Tuscany/Umbria - 4
Florence - 3
Argentario - 1
Rome - 4

You could, of course drop any 3 day segment and make this a little more comfortable. No matter what, I would include Sienna in your Tuscany/Umbria Florence segment and not wait until a travel day to Argentario to try and see it.

If you can extend until June 3, then I think that CT can probably be squeezed in then this might work;

For 19 days;

Sorrento/Positano - 4
Tuscany/Umbria - 4
Florence - 3
Cinque Terre - 2/3
Argentario - 1
Rome - 4

There are, by the way, spas all over Italy.

Deeply useful information.

thanks to everyone.....I appreciate the comments and have since changed my itinerary to leave right from Salerno or Sorrento...whichever is easiets, by train right into Siena.....where we will pick up a rental car for touring tuscany and umbria, from one hub.....staying in a agriturismo for entirely.....6-7 nights....will go into florence pisa siena perugia and assisi on day trips. We will then drop the car and train it over cinque terre for 2-3 nights before returning to Rome for 3-4 nights. flight home.
sounds cleaner, doesnt it?
Weve travelled to africa, australia, NZ and I typically keep my family running....but no complaints! it ususallly works perfectly for our family, who seem to get bored if they stay anywhere for more than 3 days....haha....
thanks again for all of your help....I now have abetter understanding of the small area that I was acutally thinking was a whole lot bigger.....

I also extrended to June 2nd departure.....we have wiggle room now!