Cycling Greece in August

Hi all in Warmshowers community!
I want to cycle a few weeks in Greece this August but have no idea where to go... Mainland Greece or the islands? How are the roads? The hosts? I've bike-toured in Portugal, Spain and Israel but have no knowledge of Greece. So welcome any any tips, route suggestions, good links or advice.
If you want to join me for part of my journey in Greece, please contact me! I'm just starting to think about it so everything is open: route, type of trip, even option for nearby countries.
I'm also thinking of spending part of August volunteering in Greece to help refugees. I speak some Arabic and have worked before with asylum seekers.
Thanks for any replies, Michael