Can't comment on Montenegro.
Sicily, we only spent time in the south and east, not that impressed, although the old town (Ortiga) at Siracusa was special and a good anchorage. Time pressures restricted adventures in Sicily (Schengen) but a friend who has spent time in the north enjoyed it very much.
Liguria is fantastic, although not a wealth of anchorages. Tuscan Islands (Elba et al) has plenty of anchoring
opportunities and easy sail to Corsica
, also Porto Venere & La Spezia. Lots of marinas
although crowded and expensive in July/August, maybe next year it will be better for visitors as I believe lots of boats have fled Italy
due to new taxation laws. We loved this region; Cinque Terre, Portofino (use Santa Margherita, Portofino way too expensive), easy access to Pisa and Florence (train from La Spezia), Genoa
(Molo Vecchio right in the old town and not expensive). Lots of history
and very nice people.