I'm exploring alternatives in light of the potential rail strike in October. One idea I'm considering is joining a tour from Rome to Pompeii and not participating in the return leg to Rome. Instead, I would arrange for a private driver from Pompeii or Naples to take me to my ultimate destination in Sorrento. I'm curious if anyone has experience with participating in only one part of a tour like this?
I haven't done that, but you'd need to contact the tour company to see whether the vehicle can accommodate your luggage and the company is willing to deal with it.
I remember a couple of years ago running into this discussion. Don't remember where. The main issue, if I remember correctly, is that if they transport you from A to B without returning to A, the tour company performs a transportation act and they are not license as a transport company. It could potentially impact their touring license so they will not do that. Given the European tendency for greater regulations in general, I could see that being a problem and a tour company not agreeing to do so.
I would think the greater probability is that the train strike will not happen. Plus there are buses to Sorrento from Roome, so take a bus.
There will always be some fast trains running-they don’t typically strike
Review the info shared in your previous post
https://community.ricksteves.com/travel-forum/italy/october-train-strike
Take a fast train to Naples then book a driver to Sorrento
Or take the ferry
Another option is shared trips.com
I believe they offer transport from Rome to Sorrento