Glad you were able to figure out something workable, sharpess. finding ferries between countries is always a challenge. Best Bet for Greece ferry-planning is to spend time on http://www.gtp.gr/RoutesForm.asp To find out ALL options between 2 places, you put in the 2 names, then the Month (6, 7 etc) and leave the DATE slot at "any." You'll then see all the options within the month... takes sorting, but u see the big picture.
IF you think there may be a ferry that's not announced yet for High Season (altho they SHOULD be on the sked by now), you could always use a "rollback calendar" feature on http://www.openseas.gr/en/index.html This website doesn't allow you to scan a whole month ... however, when you put in a definite date and click search ... the result also lets you see "Next day" and "previous day." As for "rollback", the little calendar ikon lets you turn back the calendar to LAST summer. If you want a ferry from Rhodes to Kos on the 2nd Monday of July ... roll back NOT to 2015s 2nd monday, but look at 2nd Monday of July 2014. Perhaps there's a regular sailing that just hasn't been added to the 2015 calendar yet.
For Rhodes-Santorini, Blue Star site is VERY clear: http://www.bluestarferries.com/site/content.asp?sel=624&loc=2&query= ... what trips up people going outbound is that sail-time From Santorini, just after midnight on M-W-F -- best to think of it as Sun - Tues-Thurs night Very Late. But the inbound trip no confusion.
I tend to think people get confused on ferries when they go on too many company sites. gtp.gr is TOPS. And you don't have to order online... just find ferries & book when you get to Greece, unless it's for a major holiday.
