The Greek islands are a lot of fun but a few problems that you might encounter are making contact with ATC when at lower levels as high ground will blank out the signal.
The (airline) briefing for most Greek islands includes warnings about lackluster ATC, short runways (not your problem!) high ground, wind shear & birds.
The one thing that you must get your head around is reporting your position by RAD/DIS from a nearby VOR as this is the only way to give ATC a picture of what is going on as most of the time there is no radar.
Check the avalability of fuel on a daily basis and if you can get a BP fuel card it will speed things along as most of the bowser drivers don't like cash payment (if they get it wrong it comes out of their pay).
If you have problems communicating with ATC get an Airliner to relay for you, most of us are happy to help if the workload permits.