We went the other way mid april last year. There was snow on the hills and I was forced to wear thermals and all wet weather gear
i owned for days on end. Few days later and we were in shorts. Locals said it was unseasonal so I guess be prepared for anything that time of year but you probably know that.
We wanted to go via peloponnese but ended up transiting the canal as we had over a week of unfavourable winds round the bottom but tail winds through the gulf.
The big plus of the trip is you will be in Greece
for easter - not to be missed.