Can I fit Sicily into this trip?

Sicily is a country onto itself. You can certainly visit most of the main sights of the island if you have 12 nights on the ground at your disposal (2 weeks would be better however).
If you can only spare half that (at least 6 nights) in Sicily then you can only visit one area: I would choose between either the west corner (Palermo and Trapani provinces) or the Ionian Coast on the East (basically Catania and Siracusa provinces).
Flying is a must. Getting down there from Tuscany via ground transport takes forever and a day.
For a guide look at www.bestofsicily.com

I usually discourage people from going to Sicily if they have less than 2 weeks. Eighteen days wasn't enough for me, and I didn't go to any of the isolated Greek ruins (near the top of many visitors' lists) or to the Aeolian Islands. But I didn't have a car, which slowed me down considerably. A car will make you more agile if you have time for some stops outside the key places along the rail lines. Since you go to Europe often, it wouldn't be crazy to do as Roberto suggests and think of this year as an opportunity to see a corner of Sicily, then return to see the rest later. That's assuming you can get workable and affordable flights, of course.

Rick has a new guide book just for Sicily. It post-dates my trip so I haven't read it, but I'm sure it would be a good start on figuring out a lot of what there is to see there. In addition, Rick filmed two TV shows in Sicily last year, "The Best of Sicily" and "Sicilian Delights". They are available right on this website. Follow the link, scroll down and click on "Italy".

You'll find costs in Sicily quite low except for (I assume) lodging in Taormina.

Nickelini, I agree with the others. Sicily is a large island, with very wonderful cities, towns, countryside and sites, throughout. With less than 2 weeks one can only scratch the surface, with the danger of rushing through the areas you choose to visit. How about two weeks in Sicily, one week in Switzerland, and suggest to your relatives in Lucca that they meet up with you in their choice of Sicily or Switzerland.

I suggest you get a guide book or two on Sicily from your library and decide if it interests you. I spent 2 weeks there, mostly with a car, and had to make some hard decisions about my itinerary with only 2 weeks, leaving out quite a bit because I like a slower pace. The only place I kind of "just hung out" was Ortigia (Siracusa) and that was mostly because of an unexpected knee problem. I loved it and it's the only place I think I would have enjoyed being so laid back. There were no memorable museums (nothing like those in Rome or Florence), but there were some interesting small towns and I devoted a lot of my time to the ancient Greek and Roman sights.

Except for Cefalu, I found Sicily to be cheaper than the mainland, for both hotels and restaurants.

I certainly agree with everyone here, Sicily is big with sightseeing interests spread across the island. It deserves time to really sightsee effectively. Generally speaking, your gut is correct and it’s not enough time. BUT, if you were really keen on trying to fit a taste in, then a few nights in Palermo is not the craziest idea in the world. I thought Palermo was pretty fantastic, and that it’s a city that’s not to be missed. It’s got a magic combination of history, personality, grit, and lively cosmopolitan lifestyle with a patina of old world elegance over it all. You should be able to find decent flights from the mainland. Palermo’s airport is small, and navigating between the airport and the city is easy. Accommodations and expenses are pretty reasonable. It’s certainly an added hassle and expense for you, but you may ultimately find it very rewarding.

Pretty much the only way to get any kind of a real taste of Sicily in less than a week would be with a guided tour where your transportation by coach is supplied and you have a dedicated guide so it's much more efficient. My first trip to Sicily was 6 days with a guided tour and we saw an awful lot but really what it did was whet my appetite for more. I wouldn't recommend doing it on your own in less than 2 weeks (3 would be better). If you only have a week expect to just hit the high spots in either the east or the west, not the whole island.

Thanks, everyone, for your thoughts and tips. The 2 Rick Steves videos were interesting, and I'll watch them again when I sit down to do serious planning in January. We don't stay anywhere for 2 weeks, and this was an addition to the trip I'd sketched out, so I'm still only looking at a few days in one spot. Maybe Taormina, but I'll have to do some more research.

Ah, silly me, look what I found: https://www.ricksteves.com/europe/italy/sicily-itinerary

Here's the site's recommendation:

Depending on the length of your trip, and taking geographic proximity into account, here are our recommended priorities:

4 days: Palermo (with half-day trip to Monreale for its cathedral) and Siracusa
6 days, add: Agrigento
8 days, add: Mount Etna and Taormina

Personally I disagree with that itinerary. For me, with just a few days as part of another trip, I would stay on the east coast somewhere and visit Mt Etna, Taormina, Catania, and maybe down the coast to Syracuse. I don't think I'd stay in Taormina, it's great to visit but it's not that easy to use as a base since you have to come down from there to get anywhere else. I would stay somewhere on the coast at a beach hotel - we loved where we stayed in Giardini Naxos - and visit Taormina and Etna as day trips from there. Just a personal opinion and you may disagree based on what your interests are what you want to see and do while there for just a few days.

I always disagree with the parts of Rick's itineraries that cover cities (that would be Palermo and Siracusa) as opposed to tiny towns or isolated sights. He so often allows just one day and a few hours in a place where I think 3 or 4 days (that means 4 or 5 nights) is a more reasonable time allowance. In this instance he doesn't mention the beautiful Baroque towns in southeastern Sicily, not terribly far from Siracusa: Ragusa, Noto, Modica and Scicli. There's also Cefalu to the east of Palermo. I think it would be really short-sighted to try to cover Palermo and Siracusa in just 4 days.

This forum always has great info. Thanks! I just spent some time browsing accommodation at TripAdvisor and I'm finding many gorgeous places and so much cheaper than what I'm used to paying. I'm starting to want to make this work and maybe willing to sacrifice other places I had planned to go (bye bye cooking class in Bologna!)

I like Bologna a lot, but Sicily is fabulous. It's awkward to get there, so I'm all for seeing as much of it as you can if you're going to go. It's not as easy to go back there as it is to return to Rome/Florence/Bologna/etc.

I just returned from a two week jaunt through Sicily in Late September, early October. We stayed for two nights in seven different places: Palermo, Trapani, Agrigento, Piazza Amerina (1 night), Ragusa, Ortygia, and 3 nights in Giardini Naxos. I can't imagine doing Sicily without a car, although driving the interior is a bit daunting. There is so much to see and do that even two weeks felt rushed. since it's an island, and you have to fly there, in my opinion it should be its own destination. I agree that prices for accommodations and restaurants are far below European standards making Sicily a great value for its gorgeousness.

Thanks everyone for your info -- all of it was valuable. I think the answer to my original question: Can I fit Sicily into this trip? Is, NO, unless I make a lot of changes. I think we'll save Sicily for a time when my daughter isn't living in Switzerland (because it doesn't look like that will be forever). Or for when we have more than 3 weeks. Having gone down this road, I see that I definitely want to go to Sicily at some point (which I wasn't even sure about when I posted my question). I'm surprised that when I went to my RS Italy book, he doesn't go south of Naples-Amalfi Coast (which we've done). That sort of makes me want to go more .... off the main tourist tracks and all.

Anyway, for our 2020 trip, it looks like cooking class in Bologna is back in the mix. Also, I've been trying to go to San Marino since the 1990s (because I like to go to obscure places) so maybe we'll even get there.

Rick has issued a new guide book just covering Sicily.