Montenegro and Albania offer an interesting and safe coast of transit between Croatia and Greece. With less than 60nm between ports, day sailing is feasible. It's worth spending time in Montenegro's Gulf of Kotor, or even wintering the boat in the country.
This page describes the Adriatic in general, and leads to more detailed pages about each cruising region. The sea is 420nm long and 100nm wide. The high spot is cruising Croatia, which should not be missed. There is a marked difference between the high standards of food and service in Italy, compared with the more simple standards along the eastern shores. There's more unsettled weather in the Adriatic than in other parts of the Mediterranean - with winter frosts in the north.