I am interested in driving from Olympia Greece to Delphi. Any suggestions on route and duration of travel?

The best way is probably to drive north to Patras/Rio, cross the Corinthian Gulf on the new bridge at Rio, then head east all the way to Delphi. These roads are small and (past Rio) winding, but they are scenic. It would take 1 hour to Patra, and probably another 2 hours to Delphi. Stop in Nafpaktos (just across the bridge) for food somewhere near the little harbour!