We sailed and lived aboard in Sardinia/Corse for 5 years. Normally Jul/Aug is the crowdy period, but, if you sail on the south part it is affordable and it is the best place, IMHO.
90% of the people sail on the north part and there is crowdy and expensive.
Sardinia and Corse can be done without so many Marina, you can stay all month without going into.
Otherwise, If you like to stop, it is better you reserve a transient.
is Maestrale (NW), be aware to sailig between Bonifacio straight during Maestrale over 20knts, waves are chopping and rough sailing crossing it (due to the depth
in Lion's guld adn the shallow in the passage).
Normally the sailing trip is underclockwise, we sailed up from Cagliari to the eas coast several times and there are a lot of bay and place to anchor
On the other way, from Cagliari to west is georgeus until Carloforte (San Pietro Island), look well the chart for enetring there.
Be aware the coast near Capo Teulada that is military and no anchor allowed (well marked on any chart).
Fron San Pietro Island up is difficult, against Maestrale and not a lot of place to repair. Much better reach Algero(musto to see) by the other way and stop to Asinara Island (Buoyed, no free anchor).
On the north side, a visit to Arcipelago della Maddalena, except the crowdy priod, must be done. Contact the Maddalena Park for get ticket La Maddalena e le altre isole dell'Arcipelago: Parco Nazionale dell' Arcipelago di La Maddalena
Corse: Bonifacio is really impressive the entrance, but thecity is nothing special, Ajaccio is really nice and , on the east side, some nice bay are waiting for you :-)