best place to be based to have to get to Naples from Amalfi Coast

To use public transportation, you need a bus and a commuter train. I would spend the night before departure in Napoli, which is a short taxi ride from the station to the airport.

It's not that the train is so unreliable, it's that the train doesn't go to the Amalfi Coast. The car service is affected by traffic and construction. No one with a morning flight should sleep on the AC the night before.

You would get better transportation advice if you gave the month and the day of the week. But the answer is pretty much the same. The CV train is very crowded and annoying with more than a small bag, but the price can't be beat.

There are too many variables, in my opinion, affecting your arrival at Naples airport for a departing flight. I definitely would stay the night before as close as possible to the airport. Even though we had a driver pick us up in Positano and take us to the Naples train station the driver told us they do not know what to anticipate day to day with congestion, construction and accidents that may affect getting customers to the Naples airport to catch a flight.

Similar issue for me.

I'll be in Cetera the night before my flight out of Naples, same time 11:30am. I'm hiring a car service through the hotel to bring us to airport for like $110 euros, but I'm not against cutting the loss on the last night of the hotel and going into Naples the night before. I didn't think it through until I looked at a map lol.

Why don't you just stay in Naples your last night? Your flight is not that early, and the airport is super close to the center.

Ditto to the above: I'd stay in Naples the night before to eliminate the troublesome variables and have a more leisurely pre-flight morning. Sleep in a little, do a last bit of packing, have breakfast...

If you are ok paying for a car service, a private driver can easily get you from Amalfi to the Naples Airport in time for your flight.
We stayed in Positano our last night, had a private car service pick us and drive us to the Naples Airport where we caught an 11:35 AM flight so very similar to your situation. It was very simple and relaxing.

Unless you wanted to go to Naples I would not change hotels for the last night for the flight alone.
Moving to Sorrento for one night would make no sense at all.

We used a car service also and it worked really well. Money well spent!

Thanks for the advice. We're leaving Amalfi Coast in the first days of June for Naples so it will be busy I'd expect.
People are either saying get a driver or stay in Naples the last night the last day. that is obviously going to take hours as well!

"...that is obviously going to take hours as well."

The day before your flight, you have those hours; the day of your flight, you don't have much wiggle room. You could take a late-afternoon bus and train to Napoli, stay in a hotel near the station, and get to the airport within 15 minutes the next morning.

Thanks again for your replies. it's very hard to imagine the problems we will obviously encounter with travel there. It looks like we will go to Naples for the last night but just another thought how to get there.
What are the ferries like from near Amalfi and how often do they go, is that a better and quicker option to get to Sorrento to save the slow bus trip there or is that not an option? At this stage we are staying just out of Amalfi about 5-10 mins drive I believe, so where do the ferries actually leave from? I'm mentioning Sorrento because the train, later in the day from there might not be so busy, please correct me if I'm wrong.

There are no direct ferries from Amalfi-Naples. You would have to go Amalfi-Sorrento-Naples.

The AC is not the easiest area to get around. Bus and ferry schedule here.

http://www.positano.com

Just because your dilemma is in a foreign country, it is not any different than it would be in most any vacation place in the united states.
Your choice is go to the city your airport is in the night before or pay a private driver for the direct ride in the morning.

EDIT: I just realized OP is from New Zealand, my apologizes. Still think my advise applies you are either used to this type of situation and the risks involved or you are risk adverse and will choose to be closer on the last night. Don't get caught up in thinking traffic is everywhere and much different there than anywhere else.

You are only 70 km or so away from the Airport in Amalfi and there are many professional private drivers that can monitor the situation and advise best time to pick you up so you don't miss your flight. Don't overthink it, at check in ask your hotel to make the arrangements for you, they do this all of the time and a car service wants future business so will treat their customers right.

if in the same situation in the US you would book the last night closer, than do so but otherwise don't change your plans and shorten your vacation by a day for this reason, your flight is at 11:30 AM not 7 AM.

I would feel differently if you were trying to take public transit for the trip from Amalfi to Naples Airport that morning but with a private driver I would not stress it.