No, we flew into Catania and out of Palermo and did a clockwise loop, but we had 18 days. It worked very well, but if you're staying on the west side you're absolutely right it's best to just use Palermo for in and out.

Just came to this post now - we did exactly the same trip as you're planning.

Don't take a car into Palermo, but DO take the airport bus and get your car there, on your way to Erice etc. You're on the "good" side of Palermo, avoiding the inner-city nightmare, as you make your way towards the west coast.

Make sure you stop at Segesta. We found that looking at the temple from the carpark area across the valley was much nicer than from up close - the flaws were not visible and it looked majestic! But do take the shuttle to the top and walk to the amphitheatre - priceless location and views!

Erice is very fine - walk around and get a little lost - the views from the back side are especially stunning, and the cablecar is fun, of course.

Marsala is nice around the cathedral and city hall - we lucked out on Saturday morning when everybody seems to be out and about right there. Very colorful and yet, traditional.

Don't miss the Arazzi - see www.marsalaturismo.com/?mn=1:33:0:0 - and, if you plan on staying the night in Marsala, make it at the majestic Villa Favorita - www.villafavorita.com. We stayed in one of the space-capsule or "igloo"-like huts - very different and - while not luxurious - cute and not soon forgotten.
We tried too late to book for the Marsala (fortified dessert wine) demonstration visit. Must be very popular - hey, it's good stuff...

Try not to drive into Agrigento itself, maybe as far as the train station but no further. Not only is it a medieval hilltop city with lanes where a horse-drawn cart couldn't cross with another - the "forbidden-traffic time zones" are posted so badly, you're bound to get nailed.

Give the "valley of the Temples" plenty of your time, and don't miss the museum, either, both are fabulous if you take your time. It's quite a walk from one end to the other, and then you can always call a taxi to get back - just stop by a taxi stand beforehand and ask a driver for his card; as long as you have a phone that works (we got SIM cards for our mobiles).

Walking around Palermo was great - a bit gritty and grotty, with a touch of third-world exotica but nothing threatening at all. Wear good shoes, the pavement (such as it is...) is so broken up, it's very easy to twist an ankle or worse.

Do NOT miss the Marionettes museum - stunning, not just puppets but life-size items from many countries, hundreds of them. Careful - it closes for lunch, see www.museodellemarionette.it/index.php?lang=en

Note that you can't drive anywhere near to the cathedral in Cefalu, might as well park somewhere along the Lungomare Giuseppe Giardina and walk.

Driving takes some getting used to, the Italians have a very fluid way of driving fast - rarely honking even when somebody turns in front of somebody else or cuts in on you, situations that, in the US where we "insist that we own a lane" would create road rage. "Give and take", they have it down, and their statistics show fewer accidents. Learn to go with the flow, literally, and you'll have a lot of fun.

I couldn't imagine sitting on a bus or - even less - on a train, when your car lets you stop wherever, whenever!

Enjoy!

As always, differing views on cars -- but my apologies! I noticed the question about whether you NEED a car for these areas; missed the part about HOPING to have a car. My bad.

Thanks for your great advice! Looking forward to planning this trip.