Rome to Sorrento or Positano

I suppose it depends on how you plan to do it. There's a high-speed train from Rome-Naples that takes about 70 minutes, then you would need to change to the Circumvesuviana train at Naples (it's a different train line, but located in the same station). From there, the ride to Sorrento is about an hour. I think that would be doable. However, there's no train to Positano, and for me, transferring to a bus (or car rental) after over 2.5 hours on the train would make it too much for a day trip. All travel and not enough fun.

However, there are tour operators that offer day trips to Positano/Amalfi Coast from Rome, and they would provide the transportation, so that could make it doable if you're willing to pay.

If you're interested in Pompeii, the Circumvesuviana train stops right there outside the site, so I think that's a doable day trip from Rome.

It is (crazy) if you haven't allocated enough time for Rome itself. That one takes a minimum of 4 nights/3.5 days to get your head around, IMHO.

It's not "crazy," just ill-advised. I stayed in Naples and went to Sorrento and Positano for the day, and consider it one of my great travel "mistakes." These places are to be settled into and savored; there isn't much to "see" there, and whizzing through them for they day wasn't enjoyable for me. And I was just coming from Naples, which is much closer; if I had come all the way from Rome, I'd have been really angry at the long schlep for not much.

At least with a day trip from Rome to Pompeii (also a long schlep), no one can say a half-day at Pompeii is a waste. But I really do feel that a few hours in Sorrento or Positano is a waste - particularly if you're spending a lot of time and money reaching them.

It's not "crazy," just ill-advised.

LOL, Harold, Yes, "ill advised" is a better choice of words. :O)

It ain't worth spending all that time getting there and back

Going from Rome to Positano and back in one day, gives you the right to say "I did it"---- unlikely you would say "I enjoyed it"

Rome to Sorrento and back gives you time to do a nice lunch in Sorrento, but to me the charm of Sorrento was the morning and evening, especially the evening, when the main street is closed to autos and becomes a pedestrian paradise.

Thanks - think we'll give it a pass, but open to other ideas for a day trip.

Is Ostia Antica on your radar?

Here's what you could do, that isn't crazy and maybe is even reasonable. Take the 7.22 train from Termini to Salerno. It's 1.5 hrs and costs €20. From the train station you can either take a bus along the Amalfi Coast, if there isn't a longish line, so you are sure to get a good (driver's side) seat for the scenery. Or you could walk about 2 blocks to the ferry pier. I've never taken the ferry but I suspect that you'll have decent views from a full ferry - you won't have much of any from a "bad" bus seat. The coastline is scenic from Salerno all the way to Positano and the ferries stop at most towns. If you're going in summer, it will probably be crowded and you may have long waits to board. Spend the day, return to Rome from Salerno at 7.25 pm (1.5 hrs), again for around €20.

Another possible day trip is to Orvieto. The train takes about an hour and costs €10. But the train only goes to the foot of the hill. To get up to the historic center, you need to take the funicular and then walk a few minutes or take the shuttle bus. So it's about 1.5 hours travel time.