My husband and I are planning an 8 day trip to Italy- 4 days in Sicily and 4 in Rome, we thought instead of spending a fourth day in Rome we might do a whirlwind day to Naples/Amalfi coast. Our thought was to take the train to Napels, but not sure how to get to Amalfi from there and then which tour would be best? Any thoughts/suggestions? Anyone else done this?
That would be a long day. There's been lots of discussion here about travel times and routes. To get to the Amalfi Coast you'll either take the train to Salerno and catch a SITA bus from there to Amalfi or go to Naples and take the Circumvesuviana commuter train to Sorrento and then the SITA bus from there. All in all, hard to do in a day.
You will need four days to see Rome, especially if one of those days includes your day of arrival. Stick to Rome & Sicily. I hope you are flying between Rome & Sicily.
But, since you asked: train from Rome to Naples and then tranfer to the port to take a ferry to Amalfi. Website for ferry: http://www.metrodelmare.com/
I disagree about needing 4 days to see Rome. It's a major city and you can easily spend a week exploring it, but you can see the main highlights in 2 or 3 days. It's all a tradeoff; more of a city, or get out and see something wonderful along the Amalfi coast? It's a personal decision; to me, 2 days in Rome has been enough because I don't have unlimited travel days and I wanted to explore other places.
See Ricks Italy book, or the excerpt at http://www.ricksteves.com/plan/destinations/italy/rome3.htm for a suggested itinerary in Rome. As a side note, I took a tour of the Coliseum and a twilight walking tour of Rome with guides mentioned in Ricks book and they were fantastic! I'd highly recommend doing these.
My advice to the OP is to spend a nite in Sorrento which makes the day less rushed. Leave Rome in the late afternoon and you can be in Sorrento in time for a lovely dinner, then head out bright and early in the morning to catch the SITA bus down the coast and explore Positano, Amalfi, etc.