1-2 days is not a lot of time especially, as some have mentioned, in February when weather is iffy. The other issue with weather is that with such a short time you run a risk of travel delays, or worse, cancellations getting off what ever island you choose...the rule of thumb is to always be in Athens the night before your departure from Greece.
I would consider sticking to the mainland and exploring a few more days around Athens. Nafplion comes to mind.