Naples has a core in Greece, Janina. Its a good jump of point for expansion in Greece. All of Sicily are cores and should be recovered quickly. Research-wise Govt 4 first, then land 5 or trade 7 depending on how you want to expand. Expanding into the HRE, remove the conquered provinces from the HRE with 1 magistrate will keep the Unlawful Territory event from firing? The one where the emperor demands your new province back get stiff penalties. Parma, Modena, Ferrara, Romagna, Firenze, Pisa, and Siena all have University take those and never worry about govt tech again.
So if you expand into N Africa you have to fight Mamluks, Portugal and/or Castille. Expanding to Greece places you into competition with Ottomans and maybe the GH. Expanding into Italy places you in competition with the HRE, Austria, Milan, France and whoever else guarantees the Italian minors. Oh Venice.