I started my tour in the very south of Germany at Lindau (Bodensee). From Stuttgart to Lindau by train (20 Euro with bike, now it's 22 Euro).

Then starting the tour through the Alps (Davos - Bórmio - Rovereto - Vicenza), going on to cross whole Italy, especially the passes of the Apennino and some coastlines: Chióggia - Poppi - San Marino - Cagli - Ancona - Monti Sibilini - Gran Sasso/Campo Imperatore - parco nazionale dell'Abruzzo via passo Diavolo - Monti Matese - Pompeji - Costa Amalfi - Salerno - Marina di Camerota - Páola - Cosenza - Monti Sila - Crotone - Capo Rizzuto - Monesterace Marina - Tropéa - Gambàrie (Aspromonte) - Mélito di Porto Salvo - Réggio di Calabria - (ferry) - Messina - Giardini-Naxos - Linguaglossa - Rifugio Sapienza (Etna) - Catània

I got a flight back from Catània to Stuttgart with Hapagfly/HLX (today look for: TUI-fly). About 120/130 Euro with bike including taxes. Sometimes you can get cheaper, if you are more flexible with the dates. Alternative cheap airlines are flying to Lamézia Terme or Palermo. Don't look for Réggio di Calabria - you just can take general flights by Al Italia via Milano or Napoli - very expensive. Night trains and interregional fast trains you can't take inside Italy, because you can't take the bicycle with it.