There is a general problem with back-to-backs in, as far as I'm aware, all Greek regional airports in that it's necessary to exit to landside and go back through security - you can't simply get off the plane and back on again. It's normally quick and you should comfortably make the flight, but trying to cram everything into the last day - throwing in the possibility of IrOps popping up causing a delay or cancellation and wrecking the schedule and ticketing - is incredibly risky if you're totally relying on it *and* have a connection back home to make at the end of it.

If there's no option, SKG is as good a bet as any to make the flights, but - as has been said - giving yourself some leeway would be an awful lot less stressful!