Heading back to Rome from the Amalfi Coast by way of ferry, boat or excursion - any suggestions?

Where are you staying on AC?
Why are you driving there? yikes

There are car agencies in Sorrento and Salerno

Salerno is easiest to Rome -direct fast train

Yes, drop the car in Salerno and fast train to Rome. Easy as pie. I would be in Rome for that last night though.

In your April thread, everyone discouraged you from having a car in Southern Italy, but looks like you're going to do it? Is the itinerary you posted in April still the same?
It escapes everyone how congested and difficult it is to travel in Sorrento and the Amalfi Coast. I was certainly naive before our recent trip. The public transportation is poor, the roads small and congested, the traffic miserable, and locations are far apart. Good luck!
Safe travels!

And the ferries are weather- dependent, so that if a storm comes up, they could be canceled.

Yes, many people have discouraged renting a car. I also have been assured that it is do-able so I am very confused and nervous to say the least! We are traveling with friends that have family in the Naples area. Airfare into Rome was several hundred dollars less expensive compared to flying into Naples so my children and I decided to drive the coast and stay the majority of the time close to Naples wherein we can meet up with them and meet extended family members.
We are staying in Lido di Ostia for a few days (may take public transportation into Rome for a day) moving onto Castellamare de Stabia (hoping to go to Pompei) next Vietri sul Mare wherein we will stay the longest then head back to Rome for our last day/night.
I believe a 5 hour drive from Amalfi coast back to Rome will allow for stops but I am certainly reconsidering and looking into turning in the rental car in Amalfi and taking public transportation back to Rome.
I appreciate everyone's advice - I am listening, honest....planning this trip has become super stressful.

Who told you it was doable and encouraged you?

If you are nervous and confused now-buckle up and prepare to be more stressed when there

I think the confusion here is that you're calling Stabiae and Pompeii part of the Amalfi Coast. It's not. Based on your latest description of your itinerary it appears you won't actually be driving along the Amalfi Coast if you're going from Stabia to Vietri sul Mare unless you're taking the long-cut through Positano, Amalfi, etc. Driving is probably fine back to FCO as long as you don't choose to detour along the actual coast. A ferry from Vietri sul Mure would make no sense.

Are you still planning to rent scooters?

https://community.ricksteves.com/travel-forum/italy/planning-advice-regions-rental-car-vs-public-transportation

In September we did similar, returning from Sicily, stopping in Maratrea overnight (gorgeous coastline road), then on to Rome (we actually stayed in Fiumicino the night before our afternoon flight). It was a five hour drive on highways. Adding your stop (Vietri sul Mare) shows a slight dip westward but only adds a half hour to the trip. LOL the worst part was finding the Avis return entrance at FCO (follow the signs NOT google).
Happy travels!

To the question about the scooters …I’d love to rent scooters however a previous comment has led me to believe I better take out an additional life insurance policy if doing so!…lol

I am really appreciative to receive a positive comment about driving…I appreciate the honesty in the forum but it can be a bit harsh. We are NOT NASCAR drivers but we have navigated NYC rush go hour traffic and my driver has experience driving a van in NYC, DC and the cliffs of Puerto Rico again…this does NOT fill my soul with false confidence. It’s a different country with different rules and driving styles, I get it (that’s where the stress sleeps). Our style of vacationing is to immerse ourselves in the culture find those little nooks , meet the local people. We want to see some of the historic monumental , artwork etc. our main concern with public transportation is what to do with luggage each time we move from location to location. Having to make the extra stop to unload bags before exploring or carrying the bags everywhere?
Again thank you for all the input even the information that may not be what I want to hear.

Here's hoping you file a Trip Report about your driving experience in Naples and the Amalfi Coast.

I am sure you know this but it is not a good practice to leave your luggage in the car while exploring. At the very least make sure your luggage isn’t visible in the vehicle. Ideally the luggage goes to your lodging and then you explore, otherwise you are adding more stress to your trip with worries of stolen luggage.

A. A ferry to Rome? You do know that Rome isn't on the coast?
B. The drive will be over 5 hours and would involve a drop off in Rome? The train from Salerno would take half that time, followed by a taxi to your hotel. It doesn't get any easier than that, and you have several more hours to explore in Rome. Have no idea why you would want todrop the car in Amalfi instead of Salerno.

Yes I realize Rome is not on the coast..I was just thinking outside the box. I do agree the train seems to be a better idea .Avis is offering the best rates at this time. Based on another members response it may also be easier to return the car in Salerno . We haven’t booked the rental car as of yet so I will be sure to consider this option.
Thanks again.