and welcome to the HUBB :-)
The ferry from Venice to Igoumenitsa costs 150 Euros one-way for 1 person + bike (off season). When buying the ticket in Igoumenitsa the travel agencies sometimes organise it for 100 Euros one-way. So I'd suggest to ride down to GR and return via ferry. Saves lots of time and fuel.
A very beautiful trip is along the coastal road through Croatia, Montenegro, Albania. Very scenic and lots of campsites. Albania is very cheap compared to central Europe, so there I'd take a room for the night. The main road along the albanian coast is mostly good tarmac. In the south from about Vlore it splits, the easterly route being good tarmac, the coastal route, although very beautiful, is pretty rough due to construction sites.
Only when we pause to wonder
do we go beyond the limits of our little lives.