Tips for travel to and around Sardinia

What kinds of things do you like to do? The Lonely Planet was my first stop, and I suggest perusing that or the tourism website first to narrow down your choices and pick what seems appealing to you. Then, post that here for feedback. Otherwise you just hear what others liked, which I personally don’t find very useful unless I know something about a person. For example, I’m outdoorsy, like the sea, and hiking, and visiting archaeological sites, so i immediately settled on the wild east coast of Sardinia.
Are you putting the two weeks toward Sardinia, or are you traveling in Italy and trying to include some of Sardinia? That part is not clear. You could easily fill two weeks in the island and barely scratch the surface.

The most important thing to know is how much of your 2 weeks will be spent on Sardinia. If it’s all on the island, you can see a lot and even have time to take the ferry to explore Corsica for a few days. One thing for sure is that you’ll need to rent a car to make best use of your time and destinations. Also would help to know when you’re traveling. Hotel rates on the islands take a precipitous drop after September 15th.

The best advice I can offer is to not make the same Sardinia mistake that most Americans seem to make: stop thinking of Sardinia as some tiny little island that you can knock-out in just a few days, as a quick, minor side-show from your main trip to Italy. Instead, think of it as a separate country (which in many ways it is), neither small (geographically) nor insignificant (touristically minor) nor easy to "do" in a fast, compact way.

Sardinia is big - much bigger than many first-time visitors expect it to be. It's full of cool places and great things to see and do - but those things are inconveniently scattered all around this large island. And getting around from place to place takes time. Roads are of good quality, but generally are just two-lane, and anywhere along a coastline (which is where most of us will want to go) are often quite twisty and slow going. Unless you are going to just sit in a resort your whole time there, you'll need a car - which is easy enough to rent - but driving eats up time, and some folks are expecting high speed trains. There are none of those.

I absolutely loved Sardinia. We went in the shoulder season (mid-September through early October) and spent two-and-a-half weeks there, going all around the island; we could have used at least another week there. The island is very popular during their peak summer season, July and August. You will be there then, during it's most crowded time. May-June or September into October are better times to see the place.

Honestly, if you are doing a trip to Italy (and someone's first trip there), and you have just two weeks, and your primary goal is to "see the highlights of Italy" I recommend you skip Sardinia this time. It deserves more time than you can give it, I actually think it makes an ideal destination for a dedicated 2-3 week trip of its own, like many other European countries. With just two weeks, you will already be making painful choices and tradeoffs just trying to hit all your top-priority highlights on the Italian mainland - doing that justice requires a lot longer than two weeks, but at least on the mainland there are fast, efficient trains, and a well-trod path between all the major tourist destinations. But there are a lot of those "must see" places on the mainland.

As much as I love, Sardinia, I'd save it for a time you can give it the time it deserves, maybe your 3rd or 4th trip to Italy. Because you'll be hard-pressed to check off all your "must sees" on the mainland in 2 weeks. If you're not convinced, I'd suggest you just set aside your plans for Sardinia for the moment, and first go through the exercise we all do when planning any trip: list all the places on the Italian mainland that are your "must see" places for this trip. Figure out how you would allocate available days to those places (and how to get between them). Then get out a calendar and see how many days you'll need to do them all. Count up your unused days. Then consider the trade-offs you would make to carve out some time for Sardinia.

Sorry, I know it's probably not what you wanted to hear, but I hope it's helpful in planning your time in Italy.

Gave some ideas in this old thread.
https://community.ricksteves.com/travel-forum/italy/sardinia-a4b6bf34-12f0-4f41-aa46-cc7c08ab1f7f

Sardinia is 2 and half times the size of the Big Island of Hawai'i, so 3 nights is definitely not enough.
A car is absolutely a must.