I'm a bit biased since I live here part of the year, but some of the best motorcycling is in Sardinia.
We have a place in Sant'Antioco, an island attached to the SW corner of Sardinia. The Guzzi tour goes through here. The tour is around the south end of the island. Here is a link to other resources, in case anyone wants to spend more time here touring.https://www.pastorinmoto.org/en/gli-itinera
A few notes - GPS and Google are notoriously unreliable here. They often send you down dead ends, which only become apparent after several kilometers when the road stops at a gate or fence. Or just stops. So don't be in a hurry.
Summer is not a great time for motorcycling - it's (relatively) crowded and can be very hot. Currently (Feb) it's 15 C and sunny here. however, it can be tough to find open accommodation since a lot is seasonal, but the roads are empty. Best times are after Easter before summer, or September to November. B&Bs in towns are best, and hosts can provide great restaurant recommendations. Very little vehicle traffic, but flocks of sheep, goats, cows and pigs can be found in many places. Roads are narrow and twisty, with spectacular scenery and beaches (bit cold to swim in the winter though). There are a few places where it's flat, but not much.
The ferry is about 8 hours, plus time needed to arrive ahead (there are faster ones in the summer) so it's basically a day each way if you rent on the mainland. Some ferry terminals are poorly marked (we had a hard time, even after asking for directions in Livorno).
The north is generally more expensive and well developed. The south is more wild/natural and not as geared to tourism, but there is a lot to see (just not always well advertised). English is not widely spoken in the south, but people are friendly and welcoming.
Great place to visit, well worth a trip (or a longer stay!).