Trapani--Avis Car Rental

What is your question or concern about your plan? Do you want to know just if someone among us has done it exactly between Trapani and Catania? Picking up a car at a rental car location in a city/airport and returning it at another is rather common, and as long as you do so in the same country the one way drop off fees are very low or even waived in Italy.

Sorry Roberto, I should have been more specific. I had planned on staying in Palermo for 2 days then taking the train to Cefalu 1 -2 days then taking the train to Trapani, where I would like to rent the car for further travels in Sicily.
I guess I had not thought it through, as you indicated.
I should have checked out the rates in Trapani as in comparison to Palermo. Since RS book on Sicily only mentions Avis rentals in Trapani, I should look at other car rentals. I was trying to lessen the # of days I would need one.

Last year we planned to pick up a rental in Trapani, circumnavigate the island and drop it off in Palermo, but changed our minds. Prices were ridiculously expensive. It was actually cheaper to hire private drivers. If you do go the rental route, book early, especially if you need an automatic. I don't know about now or next year, but last year, they didn't have too many cars, and their hours are limited, especially on the weekends.

In your case it would make sense to rent a car in Palermo. It would make no sense to go all the way to Trapani. All rental companies are present in the city of Palermo (or also at the PMO airport, albeit usually with higher rates).

Rental rates are high since Covid (well over $100/day), so use your rental judiciously by concentrating the days you really need a car. A car is not needed in Palermo, Monreale, and Cefalu' is an easy day trip by train. Siracusa, if you stay in Ortigia, also doesn't require a car, so you could return the car in Siracusa and find your way to Catania airport via other means. But of course it all depends on your overall itinerary. A car is definitely useful to see Sicily efficiently.

We picked up and dropped off at Catania airport. Rather than drive in Palermo, we stayed at a B&B in Monreale and took the bus into Palermo. Our rental was through Avis and it was a good experience.

I don't think the train is a good idea between Palermo and Trapani. It follows a convoluted route and takes at least 4 hr. 18 min. Currently, the trip is partly by bus, but I think the rail link has always been terribly slow. A pure-bus trip would be much faster.