We arrive in Patra by ferry from Italy in early June. Is it feasible to go from Patra to Delphi by bus and then to Athens. Then we can return to Patra by way of Corinth and Olympia. I am having trouble finding the bus connection from Patra to Delphi. Is it feasible to do this in 3 and a half days. We like to keep moving when we only have a few days.
It looks as though there are two buses a day from Patras to Delphi
Your timescale is possible but very tight. You won't have much time in either Delphi or Athens.
Delphi bus times are here
The good news is that there are several buses a day from Athens to Patras. Details here
Note you arrive and depart Athens from different bus stations.